A novel organobismuth compound, 1-[(2-di-p-tolylbismuthanophenyl)diazenyl]pyrrolidine, induces apoptosis in the human acute promyelocytic leukemia cell line NB4 via reactive oxygen species

► A novel organobismuth exhibited anti-leukemia activity via reactive oxygen species. ► Compound containing antimony in place of bismuth showed no cytotoxic activity. ► Diazenylpyrrolidine moiety and bismuth center are key to the bioactivity.