Chalcones are the condensation product of acetophenone in combination with aromatic aldehydes in the presence of strong base. Chalcones and their metal complexes having prominent role in modern coordination chemistry. These compounds possessing novel structural features, interesting spectral and magnetic properties, have been the subject of intensive research due to their importance in medical, agriculture, analytical, biological and industrial fields. A series of chalcones were prepared by claisen Schmidt condensation of substituted 3-cinnamoyl-4-hydroxy-6- methyl-2-pyrones were synthesized by base catalyzed condensation of 3-acetyl-4-hydroxy-6-methyl-2-oxa-2h-pyran (DHA) with different aromatic aldehyde. Biologically active pyrazoline derivatives were synthesized using ethanol via cyclization reaction with phenyl hydrazine hydrates from chalcones. The entire synthesized compounds were confirmed by IR, 1HNMR and Mass spectral analysis. It was found that the synthesized compounds possess standard pick at desired functional groups, protons and mass of compound. The newly synthesized pyrazoline derivatives (MBPI-MBPV) were tested for their antimicrobial activities which reflects moderate to good activity against different strain of bacterial and fungi species. The pyrazoline derivatives synthesized in this research having applicability in the medical, pharmaceutical and agricultural filed.