Separate reactions of cycloplatinated 2-tolyl- and 2-anisylguanidine complexes, [Pt{kappa(2)(C,N)}(OC(O)CF3)(S(O)Me-2)] (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) {[(sic)Pt-III{kappa(2)(C,N)}(OC(O)CF3)(2)](2)Hg-0}(mu(2)-S(O)Me-2-S,O)center dot C7H8 (3 center dot C7H8) as bright red crystals and the discrete tetrametallic complex [(sic)Pt-II{kappa(2)(C,N)}(mu(2)-OC(O)CF3)(2)Hg-I-](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 (H-1, C-13{H-1}, F-19, and Pt-195) spectroscopy. Complex 4 was also characterized by Hg-199 NMR spectroscopy. The molecular structures of 3 center dot C7H8 and 4 were determined by single-crystal X-ray diffraction studies. 1D CP 3 center dot C7H8 contains a Pt(III)-Hg(0)-Pt(III)(mu(2)-S(O)Me-2-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 center dot 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 [(sic)Pt-II(OC(O)CF3)(mu(2)-OC(O)CF3){kappa(3)mu(2)(C,N,O)}Hg-I-](2) (12), wherein each Pt -> Hg coordinate bond is supported by one mu(2)-bridging trifluoroacetate ligand and one chelating bridging guanidinate(1-) ligand, as inferred from variable-temperature H-1 and F-19 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 [Cl-2(H)C-Cl center dot center dot center dot(sic)(PtOC)-O-II((O)CF3){kappa(3)mu(2)(C,N,O)}Hg-I-](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.