Organometallic compound, organic light-emitting device including the organometallic compound, and diagnostic composition including the organometallic compound

1. An organometallic compound represented by Formula 1:

M(L 1 ) n1 (L 2 ) n2 ,  Formula 1

wherein, in Formula 1,

M is iridium,

L 1 is a ligand represented by Formula 2A,

n1 is 1 or 2, wherein, when n1 is 2, two groups L 1 are identical to or different from each other,

L 2 is a ligand represented by Formula 2B,

n2 is 1 or 2, wherein, when n2 is 2, two group L 2 are identical to or different from each other,

the sum of n1 and n2 is 3, and

L 1 and L 2 are different from each other:

wherein, in Formulae 2A and 2B,

X 1 is C,

ring CY 1 is a C 5 -C 30 carbocyclic group,

ring CY 2 is a benzene group,

ring CY 14 is a benzene group,

R 1 to R 3 are each independently a C 1 -C 60 alkyl group or a C 6 -C 60 aryl group, each independently unsubstituted or substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, and a C 1 -C 10 alkyl group,

Z 1 to Z 3 and R 11 to R 14 are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF 5 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 6 -C 60 aryloxy group, a substituted or unsubstituted C 6 -C 60 arylthio group, a substituted or unsubstituted C 7 -C 60 arylalkyl group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted C 1 -C 60 heteroaryloxy group, a substituted or unsubstituted C 1 -C 60 heteroarylthio group, a substituted or unsubstituted C 2 -C 60 heteroarylalkyl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q 1 )(Q 2 ), —Ge(Q 3 )(Q 4 )(Q 5 ), —B(Q 6 )(Q 7 ), and —P(═O)(Q 8 )(Q 9 ), wherein R 12 is neither hydrogen nor a methyl group,

a1 is an integer from 0 to 3, wherein, when a1 is two or more, two or more groups Z 1 are identical to or different from each other,

a2, a3, and b1 are each independently an integer from 0 to 20, wherein, when a2 is two or more, two or more groups Z 2 are identical to or different from each other, when a3 is two or more, two or more groups Z 3 are identical to or different from each other, and when b1 is two or more, two or more groups R 14 are identical to or different from each other,

c1 is an integer from 1 to 4, wherein, when c1 is 2 or more, two or more groups represented by

are identical to or different from each other,

when a1 is two or more, two or more groups Z 1 in the number of c1 are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

when a2 is two or more, two or more groups Z 2 in the number of a2 are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

when a3 is two or more, two or more groups Z 3 in the number of a3 are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

R 12 and R 13 are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

when b1 is two or more, two or more groups R 14 in the number of b1 are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

two or more substituents selected from Z 1 and Z 2 are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

two or more substituents selected from R 11 to R 14 are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one of R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

R 10a is selected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF 5 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 6 -C 60 aryloxy group, a substituted or unsubstituted C 6 -C 60 arylthio group, a substituted or unsubstituted C 7 -C 60 arylalkyl group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted C 1 -C 60 heteroaryloxy group, a substituted or unsubstituted C 1 -C 60 heteroarylthio group, a substituted or unsubstituted C 2 -C 60 heteroarylalkyl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q 1 )(Q 2 ), —Ge(Q 3 )(Q 4 )(Q 5 ), —B(Q 6 )(Q 7 ), and —P(═O)(Q 8 )(Q 9 ),

* and *′ in Formulae 2A and 2B each indicate a binding site to M in Formula 1,

at least one substituent of the substituted C 1 -C 60 alkyl group, the substituted C 2 -C 60 alkenyl group, the substituted C 2 -C 60 alkynyl group, the substituted C 1 -C 60 alkoxy group, the substituted C 3 -C 10 cycloalkyl group, the substituted C 1 -C 10 heterocycloalkyl group, the substituted C 3 -C 10 cycloalkenyl group, the substituted C 1 -C 10 heterocycloalkenyl group, the substituted C 6 -C 60 aryl group, the substituted C 6 -C 60 aryloxy group, the substituted C 6 -C 60 arylthio group, the substituted C 7 -C 60 arylalkyl group, the substituted C 1 -C 60 heteroaryl group, the substituted C 1 -C 60 heteroaryloxy group, the substituted C 1 -C 60 heteroarylthio group, the substituted C 2 -C 60 heteroarylalkyl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group are each independently selected from:

deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, or C 1 -C 60 alkoxy group;

a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, or a C 1 -C 60 alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 7 -C 60 arylalkyl group, a C 1 -C 60 heteroaryl group, a C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a C 2 -C 60 heteroarylalkyl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 11 )(Q 12 ), —B(Q 16 )(Q 17 ), and —P(═O)(Q 18 )(Q 19 );

a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 7 -C 60 arylalkyl group, a C 1 -C 60 heteroaryl group, a C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a C 2 -C 60 heteroarylalkyl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group;

a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 7 -C 60 arylalkyl group, a C 1 -C 60 heteroaryl group, a C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a C 2 -C 60 heteroarylalkyl group, a monovalent non-aromatic condensed a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 7 -C 60 arylalkyl group, a C 1 -C 60 heteroaryl group, a C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a C 2 -C 60 heteroarylalkyl group, a monovalent non-aromatic condensed polycyclic group, or a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, a C 1 -C 60 alkoxy group, a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 7 -C 60 arylalkyl group, a C 1 -C 60 heteroaryl group, a C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a C 2 -C 60 heteroarylalkyl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 21 )(Q 22 ), —B(Q 26 )(Q 27 ), and —P(═O)(Q 28 )(Q 29 ); and

—N(Q 31 )(Q 32 ), —B(Q 36 )(Q 37 ), or —P(═O)(Q 38 )(Q 39 ); and

Q 1 to Q 9 , Q 11 , Q 12 , Q 16 to Q 19 , Q 21 , Q 22 , Q 26 to Q 29 , Q 31 , Q 32 , and Q 36 to Q 39 are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, a C 1 -C 60 alkoxy group, a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryl group substituted with at least one selected from a C 1 -C 60 alkyl group and a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 1 -C 60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.

2. The organometallic compound of claim 1 , wherein,

in Formula 2A, ring CY 1 is selected from a cyclopentane group, a cyclohexane group, a cycloheptane group, a cyclopentene group, a cyclohexene group, a cycloheptene group, a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a cyclopentadiene group, a 1,2,3,4-tetrahydronaphthalene group, and a fluorene group, a 9H-fluorene-9-one group.

3. The organometallic compound of claim 1 , wherein,

in Formula 2B, R 1 to R 3 are each independently selected from a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a 3-pentyl group, a sec-isopentyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an isodecyl group, a sec-decyl group, a tert-decyl group, a phenyl group, a biphenyl group, or a naphthyl group, each unsubstituted or substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof.

4. The organometallic compound of claim 1 , wherein,

in Formulae 2A and 2B, Z 1 to Z 3 and R 11 to R 14 are each independently selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, —SF 5 , a C 1 -C 20 alkyl group, or a C 1 -C 20 alkoxy group;

a C 1 -C 20 alkyl group and a C 1 -C 20 alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 1 -C 10 alkyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a (C 1 -C 20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a pyridinyl group, or a pyrimidinyl group;

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo(1.1.1)pentyl group, a bicyclo(2.1.1)hexyl group, a bicyclo(2.2.1)heptyl group, a bicyclo(2.2.2)octyl group, a phenyl group, a (C 1 -C 20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, an azadibenzofuranyl group, or an azadibenzothiophenyl group, each unsubstituted or substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 1 -C 20 alkyl group, a C 1 -C 20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo(1.1.1)pentyl group, a bicyclo(2.1.1)hexyl group, a bicyclo(2.2.1)heptyl group, a bicyclo(2.2.2)octyl group, a phenyl group, a (C 1 -C 20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, an azadibenzofuranyl group, and an azadibenzothiophenyl group; and

—N(Q 1 )(Q 2 ), —Ge(Q 3 )(Q 4 )(Q 5 ), —B(Q 6 )(Q 7 ), —P(═O)(Q 8 )(Q 9 ), or —P(Q 8 )(Q 9 ), wherein R 12 is neither hydrogen nor a methyl group, and

Q 1 to Q 9 are each independently selected from:

—CH 3 , —CD 3 , —CD 2 H, —CDH 2 , —CH 2 CH 3 , —CH 2 CD 3 , —CH 2 CD 2 H, —CH 2 CDH 2 , —CHDCH 3 , —CHDCD 2 H, —CHDCDH 2 , —CHDCD 3 , —CD 2 CD 3 , —CD 2 CD 2 H, or —CD 2 CDH 2 ; and

an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a 3-pentyl group, a sec-isopentyl group, a phenyl group, a biphenyl group, or a naphthyl group, each unsubstituted or substituted with at least one selected from deuterium, a C 1 -C 10 alkyl group, or a phenyl group.

5. The organometallic compound of claim 1 , wherein

R 12 in Formula 2B is selected from:

a C 2 -C 20 alkyl group or a C 2 -C 20 alkoxy group;

a methyl group or a methoxy group, each substituted with at least one selected from a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo(1.1.1)pentyl group, a bicyclo(2.1.1)hexyl group, a bicyclo(2.2.1)heptyl group, a bicyclo(2.2.2)octyl group, a phenyl group, a naphthyl group, a pyridinyl group, and a pyrimidinyl group;

a methyl group or a methoxy group, each substituted with i) at least one selected from a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo(1.1.1)pentyl group, a bicyclo(2.1.1)hexyl group, a bicyclo(2.2.1)heptyl group, a bicyclo(2.2.2)octyl group, a phenyl group, a naphthyl group, a pyridinyl group, and a pyrimidinyl group, and ii) at least one deuterium;

a C 2 -C 20 alkyl group or a C 2 -C 20 alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 1 -C 10 alkyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo(1.1.1)pentyl group, a bicyclo(2.1.1)hexyl group, a bicyclo(2.2.1)heptyl group, a bicyclo(2.2.2)octyl group, a phenyl group, a (C 1 -C 20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a pyridinyl group, and a pyrimidinyl group; and

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo(1.1.1)pentyl group, a bicyclo(2.1.1)hexyl group, a bicyclo(2.2.1)heptyl group, a bicyclo(2.2.2)octyl group, a phenyl group, a (C 1 -C 20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, an azadibenzofuranyl group, or an azadibenzothiophenyl group, each unsubstituted or substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 1 -C 20 alkyl group, a C 1 -C 20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo(1.1.1)pentyl group, a bicyclo(2.1.1)hexyl group, a bicyclo(2.2.1)heptyl group, a bicyclo(2.2.2)octyl group, a phenyl group, a (C 1 -C 20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, an azadibenzofuranyl group, and an azadibenzothiophenyl group.

6. The organometallic compound of claim 1 , wherein,

in Formulae 2A and 2B, Z 1 to Z 3 , R 11 , R 13 , and R 14 are each independently selected from hydrogen, deuterium, —F, a cyano group, a nitro group, —SF 5 , —CH 3 , —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , groups represented by Formulae 9-1 to 9-66, groups represented by Formulae 9-1 to 9-66 wherein at least one hydrogen is substituted with deuterium, groups represented by Formulae 10-1 to 10-249, groups represented by Formulae 10-1 to 10-249 wherein at least one hydrogen is substituted with deuterium, —N(Q 1 )(Q 2 ), and —Ge(Q 3 )(Q 4 )(Q 5 ), wherein Q 1 to Q 5 are each independently the same as in claim 1 , and

R 12 in Formula 2B is selected from groups represented by Formulae 9-1 to 9-66, groups represented by Formulae 9-1 to 9-66 wherein at least one hydrogen is substituted with deuterium, groups represented by Formulae 10-1 to 10-249, and groups represented by Formulae 10-1 to 10-249 wherein at least one hydrogen is substituted with deuterium:

wherein, in Formulae 9-1 to 9-66 and 10-1 to 10-249, * indicates a binding site to a neighboring atom, Ph indicates a phenyl group, and TMS indicates a trimethylsilyl group.

7. The organometallic compound of claim 1 , wherein,

in Formula 2A, Z 1 is selected from hydrogen, deuterium, —F, a cyano group, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, —N(Q 1 )(Q 2 ), and —Ge(Q 3 )(Q 4 )(Q 5 ), wherein Q 1 to Q 5 are each independently the same as in claim 1 .

8. The organometallic compound of claim 1 , wherein

c1 in Formula 2A is 1 or 2.

9. The organometallic compound of claim 1 , wherein

the group represented by

in Formula 2A is a group represented by one selected from Formulae CY 1 (1) to CY 1 (13):

wherein, in Formulae CY 1 (1) to CY 1 (13),

Z 3 is the same as described in claim 1 ,

X 19 is C(Z 4 )(Z 5 ),

Z 4 and Z 5 are each independently the same as described in connection with Z 3 ,

a15 is an integer from 0 to 5,

a17 is an integer from 0 to 7,

a19 is an integer from 0 to 9, and

* indicates a binding site to a neighboring carbon atom.

10. The organometallic compound of claim 1 , wherein

the group represented by

in Formula 2A is a group represented by one selected from Formulae CY1-1 to CY1-56:

wherein, in Formulae CY1-1 to CY1-56,

X 1 , ring CY 1 , Z 3 , and a3 are each independently the same as described in claim 1 ,

Z 1a to Z 1d are each independently the same as described in connection with Z 1 in claim 1 , wherein Z 1a to Z 1d are not hydrogen,

X 11 and X 12 are each independently the same as described in connection with X 1 in claim 1 ,

ring CY 11 and ring CY 12 are each independently the same as described in connection with ring CY 1 in claim 1 ,

Z 31 and Z 32 are each independently the same as described in connection with Z 3 in claim 1 ,

a31 and a32 are each independently the same as described in connection with a3 in claim 1 ,

ring CY 10a is a C 5 -C 30 carbocyclic group or a C 1 -C 30 heterocyclic group,

R 10a is the same as described in claim 1 ,

aa is an integer from 0 to 10,

* indicates a binding site to M in Formula 1, and

*″ indicates a binding site to ring CY 2 in Formula 2A.

11. The organometallic compound of claim 1 , wherein

the group represented by

in Formula 2A is a group represented by one selected from Formulae CY2-1, CY2-8 to CY2-CY2-28, CY2-31 to CY2-34, CY2-37 to CY2-40, CY2-44 to CY2-46, CY2-49 to CY2-52, CY2-55 to CY2-58, and CY2-61 to CY2-64:

wherein, in Formulae CY2-1, CY2-8 to CY2-CY2-28, CY2-31 to CY2-34, CY2-37 to CY2-40, CY2-44 to CY2-46, CY2-49 to CY2-52, CY2-55 to CY2-58, and CY2-61 to CY2-64,

Z 2 is the same as described in claim 1 ,

X 22 is C(Z 22 )(Z 23 ), N(Z 22 ), O, or S,

Z 22 to Z 29 are each independently the same as described in connection with Z 2 in claim 1 ,

a28 is an integer from 0 to 8,

a26 is an integer from 0 to 6,

a25 is an integer from 0 to 5,

a24 is an integer from 0 to 4,

a22 is an integer from 0 to 2,

*″ indicates a binding site to a carbon atom of a neighboring pyridine ring in Formula 2A, and

*′ indicates a binding site to M in Formula 1.

12. The organometallic compound of claim 1 , wherein

the group represented by

in Formula 2B is a group represented by one selected from Formulae CY14-1, CY14-8 to CY14-28, CY14-31 to CY14-34, CY14-37 to CY14-40, CY14-43 to CY14-46, CY14-49 to CY14-52, CY14-55 to CY14-58, and CY14-61 to CY14-64:

wherein, in Formulae CY14-1, CY14-8 to CY14-28, CY14-31 to CY14-34, CY14-37 to CY14-40, CY14-43 to CY14-46, CY14-49 to CY14-52, CY14-55 to CY14-58, and CY14-61 to CY14-64,

R 14 is the same as described in claim 1 ,

X 14 is C(R 1 )(R 2 ), N(R 1 ), O, or S,

R 1 to R 8 are each independently the same as described in connection with R 14 in claim 1 ,

b18 is an integer from 0 to 8,

b16 is an integer from 0 to 6,

b15 is an integer from 0 to 5,

b14 is an integer from 0 to 4,

b12 is an integer from 0 to 2,

*″ indicates a binding site to a carbon atom of a neighboring pyridine ring in Formula 2B, and

*′ indicates a binding site to M in Formula 1.

13. The organometallic compound of claim 1 , wherein

the organometallic compound is represented by Formula 1A:

wherein, in Formula 1A,

M, n1, n2, X 1 , ring CY 1 , R 1 to R 3 , Z 3 , R 11 to R 13 , and c1 are each independently the same as described in claim 1 ,

T 11 is N, C(Z 1a ), or carbon linked to ring CY 1 , T 12 is N, C(Z 1b ), or carbon linked to ring CY 1 , T 13 is N, C(Z 1c ), or carbon linked to ring CY 1 , T 14 is N, C(Z 1d ), or carbon linked to ring CY 1 , at least one selected from T 11 to T 14 is carbon linked to ring CY 1 , and Z 1a to Z 1d are each independently the same as described in connection with Z 1 in claim 1 ,

T 21 is N or C(Z 2a ), T 22 is N or C(Z 2b ), T 23 is N or C(Z 2c ), T 24 is N or C(Z 2d ), and Z 2a to Z 2d are each independently the same as described in connection with Z 2 in claim 1 ,

T 31 is N or C(R 14a ), T 32 is N or C(R 14b ), T 33 is N or C(R 14c ), T 34 is N or C(R 14d ), and R 14a to R 14d are each independently the same as described in connection with R 14 in claim 1 ,

two or more groups Z 1a to Z 1d are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

two or more groups Z 2a to Z 2d are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

when a3 is two or more, two or more groups Z 3 are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

R 12 and R 13 are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

two or more groups R 14a to R 14d are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

two or more groups Z 1a to Z 1d , Z 2a to Z 2d , R 11 to R 13 , and R 14a to R 14d are optionally linked to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,

R 10a is the same as described in claim 1 ,

the bonds between N and M are coordinate bonds, and

the bonds between C and M are covalent bonds.

14. The organometallic compound of claim 1 , wherein

the organometallic compound is one selected from Compounds 1 to 102, 104 to 113, 115 to 122, 124 to 133, 135 to 142, 144 to 153, 155 to 156, 158 to 160, 170, 175, 181, 182, 184 to 194, 196 to 199, 220, 281 to 318, 320 to 322, 324 to 334, 336 to 339, 341 to 382, 384 to 394, 396 to 399, 401, 402, 404 to 407, 409 to 412, 414 to 416, and 420:

15. An organic light-emitting device comprising:

a first electrode;

a second electrode; and

an organic layer disposed between the first electrode and the second electrode and comprising an emission layer,

wherein the organic layer comprises at least one organometallic compound of claim 1 .

16. The organic light-emitting device of claim 15 , wherein

the first electrode is an anode,

the second electrode is a cathode,

the organic layer further comprises a hole transport region disposed between the first electrode and the emission layer and an electron transport region disposed between the emission layer and the second electrode,

the hole transport region comprises a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer, or a combination thereof, and

the electron transport region comprises a hole blocking layer, an electron transport layer, an electron injection layer, or a combination thereof.

17. The organic light-emitting device of claim 15 , wherein

the emission layer comprises the at least one organometallic compound.

18. The organic light-emitting device of claim 17 , wherein

the emission layer further comprises a host, and an amount of the host is greater than an amount of the at least one organometallic compound.

19. A diagnostic composition comprising the organometallic compound of claim 1 .