A systematic investigation of pyrazoline class of heterocyclic lead revealed that pyrazoline containing pharmacoactive agents play important role in medicinal chemistry. Some new1-[3-(2,4-dichloro-5-fluorophenyl)-5- (aryl)-4,5-dihydro-1H-pyrazol-1-yl] ethanone derivatives were synthesized by reacting chalcones derivatives with hydrazine hydrate in glacial acetic acid. The structural elucidation of compounds was confirmed by 1H NMR and IR analysis. The synthesized compounds were screened for the antioxidant activity by DPPH method and Hydrogen peroxide method. Also the synthesized compounds were screened for the anti-inflammatory activity by egg albumin denaturation method and Heat induced hemolytic method.