C-Amino nitrile imine has been generated as primary photoproduct (λ = 220 nm) of 5-amino-2H-tetrazole isolated in an argon matrix at 15 K. Subsequent photochemical experiments (λ = 330 nm) demonstrated that C-amino nitrile imine isomerizes to the corresponding three-membered-ring 1H-diazirine and decomposes to methylenimine. The experimentally observed νas(CNN) absorption at 1998 cm–1 and a carbenic resonance structure contribution of around 20 %, predicted by natural resonance theory calculations, demonstrate that the protoproduced C-amino nitrile imine has significant carbenic character. These results pave the way to the discovery of carbenic nitrile imines.