Heteroleptic complexes having at least one diarylamino or carbazole group, as shown in Formula (I), are provided: wherein R1, R2, R3, R4, R5, and R6 each represent mono, di, tri, tetra, or penta substitutions or no substitution; wherein Z is a single bond connecting the two phenyl rings, or is absent, wherein when Z is absent, the positions on the phenyl rings may be substituted by R5 or R6; wherein any two adjacent substituents are optionally joined together to form a ring, which may be further substituted; wherein each of R1, R2, R3, R4, R5, and R6 is independently selected from various substituents; and wherein m is 1 or 2. Devices, such as organic light emitting devices (OLEDs) that comprise phosphorescent light emitting materials are also provided.