A simple and efficient method for the synthesis of some novel 2-pyrazoline derivatives is reported. Chalcones were prepared by conventional Claisen-schmidt condensation of piperonal and substituted acetophenones. Some new N1-substituted diaryl pyrazoline derivatives have been prepared by condensation of 3,5-diaryl-2-pyrazolines with chloroacetyl chloride followed by the reaction with morpholine. The structures of the synthesized compounds were confirmed by FTIR, 1H NMR, mass spectral data. The synthesized compounds have been screened for their antimicrobial activity against different micro-organisms. A significant level of activity was observed.