4-Nitroveratrole (NVT) is photosubstituted with primary amines, piperidine and hydroxide ion. Primary amines and hydroxide ion cause replacement of the methoxy group in meta position with respect to the nitro group whereas piperidine photosubstitutes the methoxy group in para to the nitro group. Photoreactions with piperidine and hydroxide ion involve attack of the amine upon a triplet excited state of NVT. Mechanistic evidences indicate that ...