Organic electroluminescent materials and devices

1. A compound having a formula selected from the group consisting of:

wherein one of X 1 and X 2 is nitrogen, and the other one of X 1 and X 2 is boron;

wherein Y 1 and Y 2 are each independently selected from the group consisting of O, S, and NAr 3 ;

wherein L 1 and L 2 are each independently selected from the group consisting of direct bond, aryl, substituted aryl, heteroaryl, and substituted heteroaryl;

wherein Z 1 -Z 8 are each independently selected from the group consisting of carbon and nitrogen;

wherein Ar 1 , Ar 2 and Ar 3 are each independently selected from the group consisting of hydrogen, deuterium, aryl, substituted aryl, heteroaryl, substituted heteroaryl, and combinations thereof;

wherein R 1 and R 2 each independently represent mono to maximum allowable substitutions, or no substitution; and

wherein R 1 and R 2 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, halogen, alkyloxyl, aryl, heteroaryl, and combinations thereof.

2. The compound of claim 1 , wherein Y 1 is the same as Y 2 .

3. The compound of claim 1 , wherein Y 1 is different from Y 2 .

4. The compound of claim 1 , wherein Z 1 -Z 8 are each a carbon.

5. The compound of claim 1 , wherein at least one of Z 1 -Z 8 is nitrogen.

6. The compound of claim 1 , wherein L 1 and L 2 are each independently selected from the group consisting of:

7. The compound of claim 1 , wherein AO, Are and Ar 3 are each independently selected from the group consisting of:

8. The compound of claim 1 , wherein the compound is selected from the group consisting of:

9. An organic light emitting device (OLED) comprising:

an anode;

a cathode; and

an organic layer, disposed between the anode and the cathode, comprising a compound having a formula selected from the group consisting of:

wherein one of X 1 and X 2 is nitrogen, and the other one of X 1 and X 2 is boron;

wherein Y 1 and Y 2 are each independently selected from the group consisting of O, S, and NAr 3 ;

wherein L 1 and L 2 are each independently selected from the group consisting of direct bond, aryl, substituted aryl, heteroaryl, and substituted heteroaryl;

wherein Z 1 -Z 8 are each independently selected from the group consisting of carbon and nitrogen;

wherein Ar 1 , Ar 2 and Ar 3 are each independently selected from the group consisting of hydrogen, deuterium, aryl, substituted aryl, heteroaryl, substituted heteroaryl, and combinations thereof;

wherein R 1 and R 2 each independently represent mono to maximum allowable substitutions, or no substitution; and

wherein R 1 and R 2 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, halogen, alkyloxyl, aryl, heteroaryl, and combinations thereof.

10. The OLED of claim 9 , wherein the organic layer is an emissive layer and the compound of Formula I, or II is a host.

11. The OLED of claim 9 , wherein the organic layer further comprises a phosphorescent emissive dopant; wherein the emissive dopant is a transition metal complex having at least one ligand, or part of the ligand if the ligand is more than bidentate, selected from the group consisting of:

wherein each X 1 to X 13 are independently selected from the group consisting of carbon and nitrogen;

wherein X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO 2 , CR′R″, SiR′R″, and GeR′R″;

wherein R′ and R″ are optionally fused or joined to form a ring;

wherein each R a , R b , R c , and R d may represent from mono substitution to the possible maximum number of substitution, or no substitution;

wherein R′, R″, R a , R b , R c , and R d are each independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and

wherein any two adjacent substitutents of R a , R b , R c , and R d are optionally fused or joined to form a ring or form a multidentate ligand.

12. The OLED of claim 9 , wherein the organic layer is a blocking layer and the compound of Formula I, or II is a blocking material in the organic layer.

13. The OLED of claim 9 , wherein the organic layer is a transporting layer and the compound of Formula I, or II is a transporting material in the organic layer.

14. The OLED of claim 9 , wherein the OLED is incorporated into a device selected from the group consisting of a consumer product, an electronic component module, and a lighting panel.

15. A formulation comprising a compound having a formula selected from the group consisting of:

wherein one of X 1 and X 2 is nitrogen, and the other one of X 1 and X 2 is boron;

wherein Y 1 and Y 2 are each independently selected from the group consisting of O, S, and NAr 3 ;

wherein L 1 and L 2 are each independently selected from the group consisting of direct bond, aryl, substituted aryl, heteroaryl, and substituted heteroaryl;

wherein Z 1 -Z 8 are each independently selected from the group consisting of carbon and nitrogen;

wherein Ar 1 , Ar 2 and Ar 3 are each independently selected from the group consisting of hydrogen, deuterium, aryl, substituted aryl, heteroaryl, and substituted heteroaryl;

wherein R 1 and R 2 each independently represent mono to maximum allowable substitutions, or no substitution; and

wherein R 1 and R 2 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, halogen, alkyloxyl, aryl, heteroaryl, and combinations thereof.