A series of (3-phenyl-5-(1-phenyl-3-aryl-1Hpyrazol-4-yl)-4,5-dihydro-1H-pyrazol-1-yl)(pyridin-4-yl) methanones was synthesized by condensing suitably substituted chalcones, i.e., 3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)-1 phenylprop-2-en-1-ones, and isoniazid in acetic acid. The structure of newly synthesized compounds has been established on the basis of analytical and spectral data. The new compounds were screened for antimicrobial activity and most of them showed good activity comparable with that of standard drugs ciprofloxacin and fluconazole. Compounds containing methoxy group showed high antimicrobial activity.