A compound comprising a tridentate ligand LA selected from Formula I. The ligand LA is complexed to a metal M. wherein Z1 and Z2 are independently C or N, wherein if Z1 is C, then Z2 is N, or if Z1 is N then Z2 is C; X1, X2, X3, and X4 are independently selected from CR1 or N, and R1 can be the same or different for each of X1, X2, X3, and X4; X5, X6, and X7 are independently selected from CR2 or N, and R2 can be the same or different for each of X5, X6, and X7; X8 is independently selected from CR3 or N; and Y is selected from CRY or N, and RY is selected from hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, and combinations thereof, or optionally, RY can form a ring with R3. An OLED that includes an anode, a cathode, and an organic layer disposed between the anode and the cathode. The organic layer will include a compound of Formula I, and a consumer product that includes the OLED.