Four triterpenes and five flavonoids were isolated from the leaves of Bosistoa brassii (Rutaceae) and identified using spectroscopic methods. The triterpenes were characterized as baurenol and multiflorenol (isolated as a mixture), friedelan-3β-ol, and D-friedoolean-14-ene-3β,7α-diol [1]. Four of the flavonoids were identified as kumatakenin (5,4'-dihydroxy-3,7-dimethoxyflavone) [2], 5,7-dihydroxy-3-methoxy-4'-(3-methylbut-2-enyloxy)flavone [3], 5,7-dihydroxy-4'-methoxy-8-(3-methylbut-2-enyl)flavanone [4], and 5,7-dihydroxy-4'-methoxy-8-(2-hydroxy-3-methylbut-3-enyl)flavanone [5]. The fifth flavonoid is a dimer [5,7-dihydroxy-4'-methoxy-8-(3-methylbut-2-enyl)flavanon-6-yl]-[5,7-dihydroxy-4'-methoxyflavanon-8-yl]methane (6), to which we have assigned the trivial name bosistoabibvanone dimer.