Currently, researchers have given special attention to the synthesis of hetero cyclic compounds with nitrogen and oxygen five in five or sixmembered ring systems. This is mainly due to their wide range of biological activities. Hence, in this study, isoxazoline, pyrazole and bypyrimidine derivatives were synthesized from flavonoids, previously isolated from Polygonum senegalense and Psiadia panctulata, and assessed for their antifungal activity. A flavone was reacted with hydrazine hydrate to afford a pyrazole analogue 5methoxy2(5(2,3,4,5tetramethoxyphenyl)1Hpyrazol3yl)benzene1,3 diol (1) Two isoxazoline derivatives namely, 2(4,5dihydro5phenylisoxazol 3yl)5methoxybenzene1,3diol (2) and 2(4,5dihydro5phenylisoxazol 3yl)3,5dimethoxyphenol (3) were successfully synthesized by the reaction of chalcones with hydroxylamine hydrochloride. An oxime derivative (4) was also generated from a similar procedure. A reaction between a chalcone and thiourea gave a bypyrimidine derivative, 4,5dihydro6(2,4 dihydroxy3,6dimethoxyphenyl)4phenylpyrimidine2(1H)thione (5). The products were then assessed for their antibacterial and antifungal activity.All compounds showed no significant activity except compound 2 that demonstrated activity against standard antibacterial agent, Streptococcus aureus with IC 50 value of 7.56 and antifungal Candida neoformans, Candida krusei and Candida glabrata strains with IC 50 values 8.01, 8.11 and 13.74 μg/mL respectively. We, therefore, recommend synthetic optimization of com pound 2 as a potential antimicrobial agent.