Organometallic compounds comprising a phenylquinoline or phenylisoquinoline ligand having the quinoline or isoquinoline linked to the phenyl ring of the phenylquinoline or phenylisoquinoline, respectively, via two carbon atoms. These compounds also comprise a substituent other than hydrogen and deuterium on the quinoline, isoquinoline or linker. These compounds may be used as red emitters in phosphorescent OLEDs. In particular, these compounds may provide stable, narrow and efficient red emission.