Department of Chemistry, Patel J.B.R. Arts, Patel A.M.R. Commerce & Patel J.D.K.D. Science College, Borsad-388 540, Gujarat, India E-mail : shailchem@yahoo.com Department of Chemistry, Sheth L.H. Science College, Mansa, Gujarat, India Manuscript received online 25 July 2012, revised 26 July 2012, accepted 31 July 2012 Pyrazolines are well-known and important nitrogen containing 5-membered heterocyclic compounds and various methods have been worked out for their synthesis. A new series of 3-chloro-1-{ 4-[5-(substituted phenyl)-4,5-dihydropyrazol-3-yl]phenyl}-4-(4-cholorophenyl)azetidin-2.-one are synthesized by reacting 3-chloro-1-{ 4-[3-(substituted phenyl)prop2-enoyl]phenyl}-4-(4-chlorophenyl)azetidin-2-one with 99% hydrazine hydrate. All these compounds were characterized by means of their IR, 1H NMR, spectroscopic data and microanalysis. All the synthesized products were evaluated for their antimicrobial activity. All the compounds were tested for their antibacterial and antifungal activities by broth dilution method.