Treatment of [Ru(PPh 3 ) 3 Cl 2 ] with two equiv. of K[H 2 B(tim Me ) 2 ] (tim Me =N-methyl-2-mercaptoimidazol-1-yl) in tetrahydrofran (THF) at room temperature afforded a neutral complex [Ru(PPh 3 ){κ 3 -H,S,S′-H 2 B(tim Me ) 2 }{κ 2 -S,S′-H 2 B(tim Me ) 2 }] (1), while reaction of the similar reactants in THF at reflux gave a cationic complex [Ru(PPh 3 ){κ 3 -H,S,S′-H 2 B(tim Me ) 2 }(η 1 -S-Htim Me ) 2 }]Cl (2) during which the fragmentation of the ligand [H 2 B(tim Me ) 2 ] − occurred due to higher temperature. Treatment of [Ru(DMSO) 4 Cl 2 ] with two equiv. of K[H 2 B(tim Me ) 2 ] in THF solution at room temperature resulted in formation of a neutral complex [Ru{κ 3 -H,S,S′-H 2 B(tim Me ) 2 } 2 ] (3) with a [RuS 4 H 2 ] core. The crystal structures of complexes 1–3 have been determined by single-crystal X-ray diffraction, establishing the configuration and the B–H⋯Ru bonding mode of the ligands. The ruthenium atom in each of the above complexes adopts a pseudo-octahedral geometry with a three-center, two-electron B–H⋯Ru interaction. Spectroscopic and electrochemical properties of all complexes are also reported.