3-(3-Hydroxy-2-(hydroxymethyl)phenyl)propanoic acid, 2-hydroxymethyl-3-hydroxy-(E)-cinnamic acid, and colletofurans A-E were isolated from Colletotrichum boninense AM-12-2. Colletofurans A-E are the first natural compounds featuring a 1-octyl-1,3-dihydroisobenzofuran core. Their structures were initially established by 1D/2D-NMR and HRESITOFMS. Mosher's ester method was used to determine the absolute configurations of secondary alcohols in colletofurans A-C. The structures of colletofurans A and B-E were further confirmed by DFT GIAO calculations and the X-ray crystalline sponge method, respectively.