New complexes [Cr(CO)4(R2P(S)P(S)R2)] and [Cr2(CO)10(μ-R2P(S)P(S)R2)] (R = Me, Et, Pr n , Bu n ), (1a)–(1d) and (2a)–(2d) [(1a), R = Me; (1b), R = Et; (1c), R = Pr n ; (1d), R = Bu n ; (2a), R = Me; (2b), R = Et; (2c), R = Pr n ; (2d), R = Bu n ] have been prepared by the photochemical reaction of Cr(CO)6 with R2P(S)P(S)R2 (R = Me, Et, Pr n and Bu n ) and characterized by elemental analyses, FT-i.r., 31P-[1H]-n.m.r. spectroscopy and FAB-mass spectrometry. The spectroscopic data suggest cis-chelate bidentate coordination of the ligand in [Cr(CO)4(R2P(S)P(S)R2)] and cis-bridging bidentate coordination of the ligand between two metals in [Cr2(CO)10(μ-R2P(S)P(S)R2)] (R = Me, Et, Pr n and Bu n ).