The Synthesis of 5-methyl -2,4-dihydro-3H-pyrazole- 3-one is prepared by the cyclisation reaction between etylacetoacetate and hydrazine hyd rate in absolute alcohol .(compound 1). 5- methyl -2,4-dihydro-3H-pyrazole-3-one react with su bstituted benzaldehyde to prepare 4-(4- substituted benzylidene)-5-methyl-2,4-dihydro-3H-py razol-3-one (compound 2) . 4-(4- substituted benzylidene)-5-methyl-2,4-dihydro-3H-py razol-3-one and substituted benzoyl chloride and substituted benzene sulfonyl chloride and add Triethylamine1 to2 drops and stirring for 4 hr and evaporate Trietylamine on water bath a nd product of (4-Substituted benzylidene)- 3-methyl-1-(Substituted Phenyl Sulfonyl and substit uted benzoyl)-1H-pyrazol-5(4H)- one (compound 3 and 4) obtained