Allyl cyanides are found to add across alkynes in the presence of a nickel/P(4-CF(3)-C(6)H(4))(3) catalyst to give polysubstituted 2,5-hexadienenitriles with defined stereo- and regiochemistry. Use of AlMe(2)Cl or AlMe(3) as a Lewis acid cocatalyst accelerates the reaction and expands the substrate