A chloro-bridged chain complex constructed from paddlewheel-type dinuclear ruthenium(II,III) carboxylate units, [Ru2{3,4,5-(C2 H5O)3C6H2CO2}4Cl]n·1.2nC2H5OH (1·1.2nC2H5OH), was synthesized and characterized by elemental analysis and IR and UV-vis spectroscopies. The single-crystal X-ray analysis showed that the complex forms a zig-zag chain structure, in which the chloro ligands bridge the dinuclear units at the axial positions with the Ru1–Cl–Ru2 angle of 120.38(7)°. A broad band around 1144 nm and a band at 475 nm were observed in the diffused reflectance spectra and ascribed to a δ→δ* and a π(RuO, Ru2)→π*(Ru2) transitions, respectively. Temperaturedependence of magnetic susceptibility showed that the antiferromagnetic interaction between the dinuclear units is weak (zJ = −0.8 cm−1) with D value of 60 cm−1.