The synthesis, characterization, and emission properties of a series of Pt(L2)(S-S) complexes are reported. The(L2) ligands include 4,7-diphenyl-1,10-phenanthroline (Ph2phen), 4,4’-dimethyl-2,2’-bipyridine (Me2bpy), 1,5-cyclooctadiene (COD), trimethyl phosphite (P(OMe)3), and the alpha-C-deprotonated form of 2-phenylpyridine (2-phpy). The (S-S) ligands include 1-(tert-butoxycarbonyl)-1-cyanoethylene-2,2-dithiolate(tbcda), 1-(diethoxyphosphinyl)-1-cyanoethylene-2, 2-dithiolate (cpdt), cis-1,2-dicarbomethoxyethylene-1,2-dithiolate (met), and N,N-diethyldithiocarbamate (Et2dtc). The complexes are readily synthesized by the addition of the dithiolate or thiolate ligand to Pt(L2)Cl2 except for Pt(P(OMe)3)2(met), which is prepared by the addition of 2 equiv of trimethyl phosphite to Pt(COD)(met). On the basis of characterizations using NMR and infrared spectroscopies, all of the complexes are assigned square=planar coordination geometries with varying degrees of distortion determined by ligand steric and electronic effects. The assignment of square-planar coordination is confirmed by single-crystal structure determinations of Pt(Me2bpy)(met) (5) and Pt(P(OMe)3)2(met) (7). Purple crystals of Pt(Me2bpy)(met).CHCl3 (C19H19Cl3N2O4PtS2) are monoclinic, of space group P2(1)/n (No. 14), with a = 11.402(1) angstrom, b = 9.085(8) angstrom, c = 23.041(2) angstrom, beta = 97.83 (5)degrees, V = 2364.70 angstrom3, Z = 4, and final R = 0.024 (R(w) = 0.030) for 3123 unique reflections. Pale yellow crystals of Pt(P(OMe)3)2(met) (7) (C12H24O10P2PtS2) are monoclinic, of space group P2(1)/c (No. 14), with a = 11.209(3) angstrom, b = 12.250(7) angstrom, c = 16.558(4) angstrom, beta = 102.97(3)degrees, V = 2215.80 angstrom3, Z = 4, and final R = 0.047 (R(w) = 0.061) for 4092 unique reflections. The average Pt-S distance of 5 is shorter than that of 7, being 2.244(7) and 2.301(4) angstrom, respectively. The average Pt-N distance of 2.055(1) angstrom for 5 and the average Pt-P distance of 2.238(9) angstrom for 7 agree well with previously reported structural results.