The l-thia-3, 4-diazolidine-2, 5-dione functional group was shown to yield azo compounds upon photolysis. This photoreaction when combined with the known ability of this group to react in a Diels-Alder fashion or as a dinucelophile toward alkylating agents greatly increases the utility of this functionality. The dual reactivity of this group was demonstrated in the synthesis of a number of 3, 4-dialkyl-l-thia-3, 4-diazolidine-2, 5-diones. The photolysis ...