Abstract A novel series of 1, 2-benzisothiazol-3-one derivatives was synthesized and their biological activities were evaluated for inhibiting caspase-3 and-7 activities, in which some of them showed low nanomolar potency against caspase-3 in vitro and significant protection against apoptosis in a camptothecin-induced Jurkat T cells system. Among the tested compounds, compound 5i exhibited the most potent caspase-3 inhibitory activity (IC 50= ...