The structure of a neutral five-coordinated organoruthenium(0) complex [(eta(6)-C6Me6)Ru-0(bpy)] (1, bpy: 2,2'-bipyridine) was determined by X-ray diffraction analysis. The solvent-induced reversible color change based on the intercon-version between the purple Ru-0 complex 1 and a yellow Ru-II-hydride complex [(eta(6)-C6Me6)Ru-II(bpy)H](+) is presented.