The new compound [Mn(CO)(4)(S(2)PMe(2)] (A) has been prepared by the photochemical reaction of Mn-2(CO)(10) and Me(2)P(S)P(S)Me(2) in benzene solution. A single crystal X-ray diffraction study confirms that the manganese atom in A is six-coordinate with a distorted octahedral array of atoms around the metal centre: the dithiophosphinate ligand adopts a chelating bidentate mode of coordination. The two P-S distances [2.008(4) and 2.004(4) Angstrom] are equal within the limits of experimental error, as indeed are the two Mn-S distances [2.419(4) and 2.423(4) Angstrom]. The ''bite'' S ... S distance is ca 3.196 Angstrom. The Mn(CO)(4) moiety adopts local C-2v symmetry. The crystallographic data are backed up by an IR spectroscopic study.