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*S Supporting Information ABSTRACT: The known flemingins A−C (1−3) and nine new chalcones, named flemingins G−O (4−12), along with deoxyhomoflemingin (13) and emodin (14) were isolated from a leaf extract of Flemingia grahamiana. The isolated chalcones were found to have a geranyl substituent modified into a chromene ring possessing a residual chain, as shown by spectroscopic methods. The leaf extract showed an IC50 value of 5.9 μg/mL in a DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay. The chalcones flemingins A, B, C, G, and H were active in the DPPH radical scavenging assay (ED50 4.4−8.9 μM), while flemingins A and C showed cytotoxicity against MCF-7 human breast cancer cells (IC50 8.9 and 7.6 μM, respectively). Flemingia grahamiana Wight & Arn. (Leguminosae) is a shrub or semishrub reaching a height of up to 1.8 m. It is native to tropical Africa, occurring in open and wooded savannas