2-[1-(Methyl-sulfan-yl)naphtho[2,1-b]furan-2-yl]acetic acid.

The title compound, C(15)H(12)O(3)S, was prepared by alkaline hydrolysis of ethyl 2-{1-(methyl-sulfan-yl)naphtho[2,1-b]furan-2-yl}acetate. The crystal structure is stabilized by CH(2)-H⋯π inter-actions between the methyl H atoms of the methyl-sulfanyl substituent and the central benzene ring of the naphthofuran system, and by inversion-related inter-molecular O-H⋯O hydrogen bonds between the carboxyl groups.