Isoxazole derivatives possess antibacterial, antiviral, anti-fungal, anti-inflammatory insecticidal activities. Claisen- Schmidt Condensation method was adopted to get chalcones. Acetophenone on condensation with aldehyde in the presence of base produced chalcones. Chalcones were subjected for reaction with hydroxyl amine hydrochloric acid and potassium hydroxide to give isoxazoline derivative of chalcone. All the synthesized compounds have been characterized by using elemental analysis, FT-IR, 1H NMR, 13C NMR spectroscopy and further supported by mass spectroscopy. Purity of all the compounds has been checked on thin layer chromatographic plate and HPLC technique. All the synthesized compounds were tested for their antibacterial and antifungal activity in vitro by broth dilution method with two Gram-positive bacteria, two Gram-negative bacteria and two fungal strains. The biological activities of the synthesized compounds have been compared with standard drugs Benzyl pencillin and Ketoconazole. The compounds exhibited significant antibacterial and moderate antifungal activities. These compounds can be further exploited to get the potent lead compounds. The detailed synthesis and the antimicrobial screening of the new compounds are reported.