Ever since the recognition of strong pharmaceutical activities of triazoles and thiadiazoles, these scaffolds have been the subject of vigorous studies. One of the best strategies for synthesis of these azoles is dehydrocyclization of 1,4-disubstituted thiosemicarbazides, which leads to s-triazoles in alkaline media, whereas in strong acidic media 1,3,4-thiadiazoles are formed. However, the literature is riddled with contradictory communications regarding the nature of the products of such reactions under mild acidic conditions. As these compounds are not amenable to X-ray analysis, we have resorted to NMR and theoretical modelling to resolve this discrepancy. In this article, we present arguments indicating that dehydrocyclization of 4-benzoylthiosemicarbazides in glacial acetic acid leads to thiadiazole derivatives. These structural findings are augmented by studies of bioactivity of a few members of the studied class of compounds.