[en] Effect of cyano-group on hydrazine reactivity as reducing agents of Np(6) and Pu(4) ions is considered. Rate of the reaction between Np(6) and hydrazinopropionitrile in HNO₃ solutions submits to equation -d[Np(6)]dt=k[Np(6)][NCC₂H₄N₂H₄⁺]^1.1/[HNO₃], activation energy E=38.7±1.3 kJ/mol. Kinetics of reduction of Pu(4) by hydrazinopropionitrile is described by equation -d[Pu(4)]/dt=k[Pu(4)][NCC₂H₄N₂H₄⁺]/[HNO₃]^1.5, activation energy E=37.9±8.2 kJ/mol. Comparison of kinetic data for Np(6) and Pu(4) reactions with hydrazinopropionitrile with data for reaction of these elements with other substituents of hydrazine shows that in the same conditions (25 Deg C, [HNO₃]=1 mol/l, μ=2, concentration of reducing agents - 0.1 mol/l) hydrazinopropionitrile reduces Np(6) up to Np(5) fifty times faster than unsubstituted hydrazine and 2.4 times faster than β-oxyethylhydrazine. Analogues comparison for reduction of Pu(4) shows that proportion of rate constants of hydrazine, β-oxyethylhydrazine and hydrazinopropionitrile is 1:70:400