The flavonoids of Crotalaria grahamiana (family Pop ilionaceae) were isolated from the alcoholic extrac t by partition with benzene, diethyl ether, ethyl acetat e respectively. On the basis of chemical and spectr al analysis their structures are elucidated as 4’hydroxy flavone-7-O- rhamnoside and its aglycone.Identification of unkno wn compounds were established through comparison of ch romatographic and spectral data (PC, UV, and NMR) w ith literature values. Isolated yellow pigment for furt her studies was promoted to anti-microbial and SRBC membrane stabilization. It reveals that isolated compound sh ows significant antimicrobial and anti inflammatory activity.