The synthesis, characterization, and photophysical properties of a wide variety of bis-cyclometalaed Pt(IV) complexes featuring a C-2-symmetrical or unsymmetrical {Pt-(ppy)(2)} unit (sym or unsym complexes, respectively; ppy = C-deprotonated 2-phenylpyridine) and different ancillary ligands are reported. Complexes sym-[Pt(ppy)(2)X-2] (X= OTf-, OAc-) were obtained by chloride abstraction from sym-[Pt(ppy)(2)Cl-2] using the corresponding AgX salts, and the triflate derivative was employed to obtain homologous complexes with = F-, Br-, I-, trifluoroacetate (TFA(-)). Complexes unsym-[Pt(ppy)(2)(Me)-X] (X = OTf-, F-) were prepared by reacting unsym-[Pt(ppy)(2)(Me)Cl] with AgOTf or AgF, respectively, and the triflate;derivative was employed as precursor for the Synthesis of the homologues with X = Br-, I-, or TFA(-) through its reaction with the appropriate anionic ligands. The previously reported complexes unsym-[Pt(ppy)(2)X-2] (X = Cl-, Br-, OAc-, TFA(-)) are included in the photophysical study to assess the influence of the arrangement of the cyclometalated ligands. Density functional theory (DFT) and time-dependent DFT calculations on selected derivatives were performed for a better: interpretation of the-observed excited state properties. Complexes sym-[Pt(ppy)(2)X-2] (except X = I-) exhibit phosphorescent emissions in fluid solutions at 298 K arising from essentially (LC)-L-3(ppy) excited states, which are very similar in shape and energy. However, their efficiencies are heavily dependent on the nature of the ancillary ligands, which affect the energy of deactivating ligand-to-ligand charge transfer (LLCT) or ligand-to-metal charge transfer (LMCT) states. The fluoride derivative sym-[Pt(ppy)(2)F-2] shows the highest quantum yield of this series (Phi = 0.398), Mainly because the relatively high metal-to-ligand charge transfer admixture in its emitting state leads to a high radiative rate constant. Complexes unsym-[Pt(ppy)(2)X-2] emit from (LC)-L-3(ppy) states in frozen matrices at 77 K, but their emissions are totally quenched in fluid solution at 298 K because of the presence of low-lying, dissociative LMCT excited states, which also cause photoisomerization reactions Complexes unsym-[Pt(ppy)(2)(Me)X] (X = F-, Cl-, Br-, TFA(-)) show strong emissions in fluid solutions at 298 K (Phi = 0.52-0.63) because deactivating LMCT states lie at high energies. However, derivative unsym-[Pt(ppy)(2)(Me)I] is only weakly emissive at 298 K because of the presence of low-lying LLCT [p(I) ->pi*(ppy)] states.