The preparation of complexes of transition metals with the new ligand sulphur bis(t-butylimide) is described. Complexes [M(CO)4{S(NBut)2}](I; M = Cr, Mo, and W), [MCl2{S(NBut)2}2](II; M = Pd or Pt), and [PtCl2{S(NBut)2}(NH2But)], (III), have been characterised by analytical and spectroscopic methods. The i.r., 1H n.m.r., and mass spectra of the complexes are discussed and structures are assigned.