Organic electroluminescent materials and devices

A compound comprising a ligand LA of Formulae I, II, or IIIwherein the ligand LA is coordinated to a transition metal M, and optionally, M is also coordinated to a ligand LB;A is N, B, or CR7;Y is absent, or selected from the group consisting of C(O), C(Rya)(Ryb), C═C(Rya)(Ryb), and Si(Rya)(Ryb), where if Y of Ring A is absent then ring carbon of R2 is bonded to N; wherein for the compounds of formula III at least one of R2, R3, and R4 is selected from N(Ar1)RN′ or aryloxy; wherein Ar1 is selected from aryl or heteroaryl, each of which is optionally substituted. An OLED that includes an organic layer disposed between an anode and a cathode, and the organic layer includes a compound comprising a ligand LA of Formulae I, II, or III above. The OLED can be incorporated into one or more of a consumer product, e.g., an electronic component module, a flat panel display, e.g., a display for a phone, television, laptop, and/or a lighting panel for either commercial or residential applications.