Anadolu University, Faculty of Pharmacy, Deparment of Pharmaceutical Chemistry, Eskisehir, Turkey DOI : 10.12991/2013171314 In the present study, a series of pyrazoline derivatives were synthesized. The chemical structures of the compounds were elucidated by IR, ¹H-NMR, ¹³C-NMR and FAB+- MS spectral data and elemental analyses. The synthesized compounds were screened for their antimicrobial activities. All compounds exhibited the highest antibacterial activity against P. aeruginosa. All compounds except compounds 1-(chloroacetyl)-3-(2-furanyl)-5-(4- chlorophenyl)-2-pyrazoline and 1-(chloroacetyl)-3-(2-thienyl)-5-(3,4-methylenedioxyphenyl)- 2-pyrazoline are more effective than ketoconazole against C. albicans, whereas compounds 1-(chloroacetyl)-3-(2-furanyl)-5-(4-chlorophenyl)-2-pyrazoline, 1-(chloroacetyl)-3-(2-thienyl)- 5-(3,4-methylenedioxyphenyl)-2-pyrazoline and ketoconazole showed the same level of antifungal activity against C. albicans. Keywords : pyrazoline, amide, furan, thiophene, antimicrobial activity