A platinum (II) complex of general formula (II), in which Ar1 is a 1,2-diazole ring, Ar2 is a pyridine ring, and Ar3 is a phenyl ring. Ar1, Ar2, and Ar3 together form a tridentate ligand coordinated to the platinum through atoms X, Y, and Z, respectively, and X, Y, and Z are independently carbon or nitrogen. V represents O, S, N, C, P, or Si, and W is an anion. In some cases, Ar3 is an anion and Ar1 and Ar2 are neutral; in other cases, Ar1 and Ar3 are neutral and Ar2 is an anion. The complexes emit in the UV to near IR range and are useful as emitters for organic light emitting devices.