A compound having a structure of Formula M(LA)x(LB)y(LC)z, where ligand LA is ligand LB is and ligand LC is is disclosed. In Formula M(LA)x(LB)y(LC)z, M is a metal having an atomic number greater than 40; x is 1, 2, or 3; y and z are 0, 1, or 2; x+y+z is the oxidation state of metal M; Z1-Z6 are each C or N; ZD is N or a carbene carbon; rings C and D are independently a 5 or 6-membered carbocyclic or heterocyclic ring; R4 is substituted, while each of R1, R2, R3, RC, RD, R11, R12, and R13 are selected from hydrogen and a variety of moieties; and any adjacent substituents of R1, R2, R3, R4, RC, RD, R11, R12, and R13 are optionally joined to form a ring. Formulations and devices, such as an OLEDs, that include the compound of formula M(LA)x(LB)y(LC)z are also described.