A series of 5-(Substituted-phenyl)-3-(furan-2-yl)-4,5-dihydro-1H-pyrazole were synthesized which contained pyrazole and furan ring in their ring structure. The target compound was synthesized by the reaction of hydrazine hydrate with various chalcone in the presence of ethanol. The intermediate chalcone was synthesized reaction of various acetophenone with furfural aldehyde in the presence of ethanol. All compounds were screened for their in-vitro antimicrobial activity against five bacterial strains Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermis and Escherichia coli, Pseudomonas aeruginosa, (Gram-negative) and on two fungal strains Aspergillus niger and Candida albicans by serial two-fold dilution method and the minimum inhibitory concentration (MIC) was determined. On the bases of structure activity relationship (SAR) study it was found that electron-withdrawing or halogens groups contained phenyl ring had found effectively antimicrobial activity. In, conclusion it was found that it was found that compound 2 (R=NO2) was most potent compound of this series due to presence of NO2 group.