In the present investigation, 4-hydroxy-3-methylacetophenone, on condensation with appropriate aldehydes in methanolic potassium hydroxide solution, yielded the corresponding chalcones (CI-XI). These corresponding chalcones were reacted with phenyl hydrazide in glacial acetic acid, which led to the formation of novel 4-[5-(substituted phenyl)-1-phenyl-4,5-dihydro-1H-3-pyrazolyl]-2-methylphenol derivatives. All newly synthesized compounds were evaluated for their antimycobacterial activities against isoniazid-resistant Mycobacterium tuberculosis using agar dilution. 4-[5-(4-Fluoro phenyl)-1-phenyl-4,5-dihydro-1H-3-pyrazolyl]- 2-methylphenol showed good antimycobacterial activity, with a minimum inhibitory concentration of 0.62 mg/ml.