From the aerial parts ofBosistoa selwynii(Rutaceae) four novel prenylated acetophenones were isolated and identified as pyranoselwynone (5-hydroxy-6-acetyl-{6,6-dimethyl-5ξ-hydroxy-4,5-di-hydropyrano}-[3,2-h]-2,2-dimethylbenzopyran), selwynone (5,7-dihydroxy-6-acetyl-8-(3-methylbut-2-enyl)-3,4-dihydro-2,2-dimethyl-3ξ-hydroxypyran), furanoselwynone (5-hydroxy-6-acetyl-{5-[1-hydroxy-1-methylethyl]-4,5-dihydro-furano}-[3,2-h]-2,2-dimethylpyran), and isofurano-selwynone (7-hydroxy-8-acetyl-{5-[1-hydroxy-1-methylethyl]-4,5-dihydrofurano}-[3,2-f]-2,2-dimethylpyran). Other compounds isolated were a series of eight acridone alkaloids (reported on previously), the coumarins scopoletin and braylin and the triterpenes lupeol and β-amyrin. The structures of the new acetophenones were elucidated on the basis of NMR spectral data.