A range of bis(alkylidynyl)phosphines RP{C[triple bond, length as m-dash]M(CO)2(Tp*)}2 (M = Mo, W; R = Cl, Ph, Cy; Tp* = hydrotris(dimethylpyrazolyl)borate) are obtained from the reactions of [M([triple bond, length as m-dash]CLi)(CO)2(Tp*)] with Cl2PR or alternatively via the palladium(0)-mediated reactions of [W([triple bond, length as m-dash]CBr)(CO)2(Tp*)] with RPH2 (R = Py, Cy). The complexes RP{C[triple bond, length as m-dash]W(CO)2(Tp*)}2 rearrange slowly (R = Cl) or on heating (R = Ph) to afford the isomeric phospha-acyls [W2(μ:η1-C;η2-C,P-CCPR)(CO)4(Tp*)2].