Cyclometalated Platinum Compounds from Competing C–H/C–X Bond Activation Pathways

X-C^N^N (X = Br, Cl) ligands were reacted with [Pt₂Me₄(μ-SMe₂)₂], <b>1</b>, resulting in a six-coordinate cyclometalated platinum-(IV) compound containing an anionic C^N^N ligand when X = Br and both a platinum-(IV) and a platinum-(II) product when X = Cl. The platinum-(II) species was formed by C-H activation, followed by reductive elimination of methane. The platinum compounds were characterized by multinuclear NMR spectroscopy and single-crystal X-ray diffraction (SCXRD). Photophysical properties were explored by using UV/vis, emission, and transient absorption (TA) spectroscopies. DFT and TDDFT calculations were performed to examine the competition between C-H activation and C-X oxidative addition and compared to experimental results.