Abstract Three series of novel heterocyclic compounds (3a–3g, 4a–4g and 5a–5g) containing benzenesulfonamide moiety and incorporating a 1, 2, 4-triazole ring, have been synthesized and investigated as inhibitors against four isomers of the α-class carbonic anhydrases (CAs, EC 4.2. 1.1), comprising hCAs I and II (cytosolic, ubiquitous isozymes) and hCAs IX and XII (transmembrane, tumor associated isozymes). Against the human ...