In present study, a series of chalconesemicarbazones was synthesized, characterized and evaluated for their reducing power assay. Most of the compounds were found to be potent antioxidant. Free radicals play an important role in various pathological and xenotoxic effects so antioxidant may have protective role in these pathological conditions. Based on the results of reducing power assay an anti-oxidant study, 1-[1-{4-aminophenyl-3-(4- chlorophenyl)}allylidene]-4-o-tolylsemicarbazide (Compound 26) was the most active compound. It was found that Chloride substitution in aldehydic and amino substitution in acetophenic moiety of chalconesemicarbazones exhibited potent reducing power and unsubstituted compound showed less reducing potential.