Amination of naphtho[1,8-de]triazine with aqueous hydroxylamine-O-sulphonic acid gives 1-aminonaphtho-[1,8-de]triazine and 1-amino-8-azidonaphthalene. Amination with ethereal chloramine gives 1- and 2-aminonaphthotriazines and the latter was shown to rearrange to the amino-azide under the conditions of the hydroxylamine-O-sulphonic acid amination. Both 1 - and 2-aminotriazines are rearranged smoothly by acid to the aminoazide. The stability of these triazines is compared with that of related triazoles, and mechanisms for their rearrangements are proposed.