The synthesis and evaluation as hypoxic selective cytotoxins of 2-amino- or 2-hydroxyphenazine 5,10-dioxide derivatives and reduced analogues are reported. In vitro cytotoxicities on V79 cells under hypoxic and aerobic conditions were determined. Some derivatives, such as 7(8)-bromo-2-hydroxyphenazine 5,10-dioxide, showed selective toxicity toward hypoxic cells and along with derivatives 7(8)-bromo-2-aminophenazine 5,10-dioxide and 7(8)-chloro-2-aminophenazine 5,10-dioxide behave as hypoxic trigger cytotoxins. These compounds represent interesting leads for further chemical modifications and biological studies.