The free nido-diphosphine anions [(PR2)(2)C2B9H10](-) (R = Ph, Pr-i) show luminescence properties whereas the closo-diphosphines [(PR2)(2)C2B10H10] do not. Four families of three-coordinate complexes of stoichiometry [Aut{(PR2)(2)C(2)Bj(10)H(10)}L]OTf (L = tertiary phosphine) and [Au{(PR2)(2)C2B9H10}L] have been studied in order to analyze the influence of the closo- or nido-nature of the diphosphine, the monophosphine coordinated to gold and the substituent at the diphosphine on the luminescence of the complexes. Only the nido-derivatives show luminescence. The maxima of the emissions are shifted to lower energies than those of the corresponding free nido-diphosphines. When the substituent at the diphosphine is phenyl, a new emission appears, which has been assigned as arising from a metal to ligand charge transfer [Au-->pi*(L)] excited state.