The Rh-III(Br8TMPyP)(5+) showed a catalytic DNA cleavage in the presence of ascorbic acid. The UV-visible, Cyclic Votlammetric (CV) and Electron Spin Resonance (ESR) data confirmed involvement of the reduced form of the Rh-III-Br8TMPyP, Rh-III(Br8TMPyP)(4+.) radical, in the catalytic cycle. Gel-electrophoresis, results revealed that, Rh-III(Br8TMPyP)(5+) could cleave DNA at 0.01-0.1 mu M levels which is significantly higher than that of other metalloporphyrins.