A series of 3-[3-(2,4-dichloro-5-fluorophenyl)-5-(2-furyl)-4,5-dihydro-1H-pyrazol-1-yl]-5-(substituted phenyl/2-thienyl)isoxazolines (4a-j) were prepared. The structures of the isoxazoline derivatives were confirmed on the bases of elemental analysis and spectral data. The compounds were screened for their in vitro antibacterial activity using gram-positive bacteria and gram-negative bacteria.