Two series of oxime esters containing the 2,6-diazaanthracene-9,10-dione bis-(O-benzoyloxime) and 4,5-diazafluoren-9-one O-9-benzoyloxime moieties have been synthesized and tested as photo-induced DNA cleaving agents. All these compounds were found to cleave DNA upon irradiation with 312 nm UV light. The structure-activity relationship of these molecules for DNA cleavage was established. A plausible reaction mechanism is also proposed.