1-{4-[(4-nitrobenzyl)oxy]phenyl}ethanone 3 was prepared by condensation 4-hydroxy acetophenone 1 4-nitro benzyl bromide 2 in acetonitrile. The reaction of 3 with various aromatic aldehyde to give chalcones 4 which on reaction with hydrazine hydrate in catalytic amount of glacial acetic acid to give Pyrazolines 5. The newly synthesized compounds have been characterized by IR, 1H NMR, MASS Spectra. The synthesized compounds were screened for antimicrobial activity. The purity of synthesized compound was confirmed by TLC.