A novel Pt(III)-Pt(III) neutral dimer complex, Pt-2(cdtb)(4)I-2 (cdtb: 4-cyanodithiobenzoate) was successfully synthesized by the solvothermal method. Single-crystal X-ray structure analysis clearly revealed its molecular structure, where the Pt-Pt distance was 2.582(1) angstrom. Characteristic vibration modes and absorption bands derived from the Pt dimer structure were clearly observed in Raman and electronic absorption spectra, respectively, and the results were supported by density functional theory calculations.