Some new 1-hydro-3(1-napthyl amino)-5-aryl-2-pyrazolines 2(a-h) and 3-(1-napthyl amino)- 5-aryl-2-isoxazolines 3(a-h) were synthesized by reacting 1-(napthyl amino)-3-aryl-2- propene-1-ones 1(a-h) with hydrazine hydrate and hydroxyl amine hydrochloride in ethanol under reflux condition, respectively. Structures of the synthesized compounds were confirmed by the spectral analysis. Antibacterial activity of these compounds is also reported. Keywords:1,3-diaryl-2-propen-1ones, pyrazolines, isoxazolines, antibacterial activity;