The esters 1 of N-hydroxy-2-thiopyridone react smoothly at room temperature in a thermal reaction with diethyl azodicarboxylic ester to furnish adducts 2 of a novel structure. Photolysis of these adducts affords a convenient route to the little known tetrazanes 8. Azo compounds without electron withdrawing groups do not react. The Cookson reagent, however, is so reactive that it gives diacyl derivatives