Reactions of K-1.62[Pt(ox)(2)]center dot 2H(2)O and [Cu(bpy)(H2O)(3)](NO3)(2) yielded partially oxidized one-dimensional (1D) bis(oxalato)platinates of [Cu(bpy)(H2O)(n)](6)[Pt(ox)(2)](7)center dot 7H(2)O (n = 2, 3, or 4) (1) and [Cu(bpy)(H2O)(n)](8)[Pt(ox)(2)](10)center dot 8H(2)O (n = 3 or 4) (2). The average oxidation numbers of the platinum ions in 1 and 2 are +2.29 and +2.40, respectively. Complexes 1 and 2 crystallize in the triclinic P (1) over bar and monoclinic C2/c space groups, respectively, and the [Pt(ox)(2)](n-) anions are stacked along the crystallographic b axis with 7-fold periodicity for 1 and 10-fold periodicity for 2. In 1, an oxalato ligand in the platinum chain directly coordinates to a paramagnetic [Cu(bpy)(H2O)(3)](2+) ion, whereas no such direct coordination was observed for 2. The electrical conductivity of 2 at room temperature along the platinum chain is approximately 3 orders of magnitude smaller (sigma(II) = 1.3 x 10(-3) S cm(-1)) than that of 1(sigma(II) = 0.9-0.5 S cm(-1)), and the activation energies of 1 and 2 are 29 and 67 meV, respectively. The longest inter-platinum distances in 1 and 2 are 2.762 and 3.0082 angstrom, respectively, and this is responsible for the lower electrical conductivity of 2. An X-ray oscillation photograph taken along the b axis of 1 reveals the 7-fold periodicity in the 1D chain, consistent with the period of the Peierls distortion estimated from the degree of partial oxidation. The semiconducting state of 1 can therefore be regarded as a commensurate Peierls state. The magnetoresistance of 1 at ambient pressure indicates no interaction between conduction electrons in the platinum chain and local spins of the paramagnetic Cu-II ions. Application of hydrostatic pressures of up to 3 GPa enhances electrical conduction, as is often seen as the usual pressure effect on the electrical conductivity, which is due to enhanced orbital (Pt-5d(z)(2)) overlap by pressure application.