Mixed-metal complexes constructed from dinuclear ruthenium(II,III) carboxylates and tetracyanidoplatinate(II), [{Ru2(O2CCH3)4}2Pt(CN)4]·2H2O (1) and [{Ru2{O2CC(CH3)3}4}2Pt(CN)4]·2H2O (2), were synthesized and characterized by elemental analysis and IR and UV-vis spectroscopies. These data are in accordance with the formulation of the PtRu4 complexes with two lantern-type dinuclear Ru2 and Pt(CN)4 units. A broad band at near-IR and a distinctive band at visible region (1088 and 443 nm for 1 and 1090 and 446 nm for 2), which can be ascribed to a δ(Ru2)→δ*(Ru2) and a π(RuO, Ru2)→π*(Ru2) transitions, respectively, were observed in the diffused refl ectance spectra. Temperature-dependence of magnetic susceptibilities (4.5—300 K) showed that antiferromagnetic interaction between the two 3/2 spins of the Ru2 units through tetracyanidoplatinate(II) is weak (zJ = −0.1 cm−1) with zero-fi eld-splitting values of 45 and 65 cm−1 for 1 and 2, respectively.