The complex Ru{C≡CC(CN)═C(CN)₂}(dppe)Cp* (1), containing the new tricyanovinylethynyl (3,4,4-tricyanobut-3-en-1-ynyl) ligand, undergoes ready substitution of the 3-cyano group by nucleophiles (Nu) such as H, Me, Pri, Bu, But, mesityl, OMe, OBut, OCH2CH═CH₂, NHEt, NEt₂, and PPh₂ to give Ru{C≡CC(Nu)═C(CN)₂}(dppe)Cp*. The X-ray diffraction structures of several of the resulting complexes are reported and, for the mesityl and PPh₂ products, show that isomerization to the 3,5-dimethylbenzyl and oxidation to the phosphine oxide have respectively occurred.