The reaction of primary amines with succinonitrile leads to the formation of N,N,N′,N′-tetrasubstituted amidines and the liberation of 2 M of NH3. The reaction of secondary amines with succinonitrile proceeds as an intramolecular condensation with the liberation of 1 M of NH3 per mole of the dinitrile and the formation of the Δ2,5−α, α′-dialkylaminopyrrolene.