Novel phosphorescent tetradentate platinum compounds of Formula I are provided. The complexes contain a dibenzo moiety, which allows for the creation of OLED devices with improved properties when compounds of Formula I are incorporated into such devices. Compounds of Formula I′ that comprise two ligands that contain a 5-membered carbocyclic or heterocyclic ring, one of which contains an imidazole ring with a twisted aryl group attached to N−1 and a second aromatic ring that is attached to the platinum via a carbon atom. These compounds may be advantageously used in OLEDs.