Reactions of Group 8 metal ethynyls with tetracyanoethene afford tricyanovinylethynyl–metal derivatives, M{C≡CC(CN)=C(CN)2}(PP)Cp’ [2; M = Ru, Os; PP = (PPh3)2, dppe;Cp’=Cp,Cp*; not all combinations]; a similar reaction occurs with the vinylidene RuCl(=C=CHPh)(PPh3)Cp. Further replacement of a CNgroup in 2 occurs with nucleophiles, while homo- and hetero-metallic derivatives are obtained by coordination of one of the remaining CN groups to other metal–ligand fragments.