4, 5-Dinitroveratrole is effectively photosubstituted by amines with relatively high ionization potential such as methylamine, n-butylamine and ethyl glycinate, but is mainly photoreduced when amines with relatively low ionization potential, such as dimethyl or trimethylamine are used. The photoreduction of several aromatic dinitrocompounds by triethylamine gives nitroanilines. A mechanistic scheme is proposed embracing our photosubstitutions and ...