Separate reactions of cycloplatinated 2-tolyl- and 2-anisylguanidine complexes, [Pt{κ2(C,N)}(OC(O)CF3)(S(O)Me2)] (1 and 2), with Hg(OC(O)CF3)2 in 1:0.5 and 1:1 molar ratios afforded the one-dimensional coordination polymer (1D CP) {[PtIII{κ2(C,N)}(OC(O)CF3)2]2Hg0}(μ2-S(O)Me2-S,O)·C7H8 (3·C7H8) as bright red crystals and the discrete tetrametallic complex [PtII{κ2(C,N)}(μ2-OC(O)CF3)2HgI-]2 (4) as yellow crystals in good yields. The two different products obtained in the aforementioned reactions are ascribed to the subtle differences in the N substituent of the guanidinate(1-) ligands in 1 and 2. The plausible mechanisms of formation of 3 and 4 are outlined. Complexes 3 and 4 were characterized by elemental analyses and IR and multinuclear NMR (1H, 13C{1H}, 19F, and 195Pt) spectroscopy. Complex 4 was also characterized by 199Hg NMR spectroscopy. The molecular structures of 3·C7H8 and 4 were determined by single-crystal X-ray diffraction studies. 1D CP 3·C7H8 contains a Pt(III)-Hg(0)-Pt(III)(μ2-S(O)Me2-S,O) repeating unit with a pair of unsupported Pt-Hg covalent bonds, while 4 contains a Pt(II)-Hg(I)-Hg(I)-Pt(II) chain with a pair of trifluoroacetate ligand supported Pt→Hg coordinate bonds. 1D CP 3·C7H8 falls apart into a mixture of three species, namely 6-8 and 9-11 in C6D6 and CDCl3, respectively, as revealed by multinuclear NMR spectroscopy. In CDCl3, 4 partially isomerizes to [PtII(OC(O)CF3)(μ2-OC(O)CF3){κ3μ2(C,N,O)}HgI-]2 (12), wherein each Pt→Hg coordinate bond is supported by one μ2-bridging trifluoroacetate ligand and one chelating bridging guanidinate(1-) ligand, as inferred from variable-temperature 1H and 19F NMR spectroscopy. Complex 12 is the major species and 4 is the minor species in CDCl3, while opposite situation prevails in C6D6. The observance of a mixture of two solution species for 4 is ascribed to a rapid "carboxylate shift" process induced by the oxygen atom of the ═N(C6H4(OMe)-2) unit of the guanidinate(1-) ligand through neighboring-group participation. UV-visible absorption and emission spectra of 4 were measured in CHCl3, and from the outcome of the investigation, the possible existence of [Cl2(H)C-Cl···PtII(OC(O)CF3)(μ2-OC(O)CF3){κ3μ2(C,N,O)}HgI-]2 (12″) was suggested, which is likely to have a pair of Pt-Hg covalent bonds made possible by CHCl3 coordination on the sixth site of the Pt(II) atom.