Novel iridium complexes containing phenylpyridine and pyridyl aza-benzo fused ligands are described. Iridium complexes containing aza-benzo fused ligands in which an aryl group is conjugated to the aza ring of the specific aza-dibenzofuran ring system results in the formation of yellow phosphorescent compounds with superior device stability and efficiency. These complexes are useful as light emitters when incorporated into OLEDs.