2-(3-Ethyl­sulfanyl-5-fluoro-1-benzofuran-2-yl)acetic acid

The title compound, C(12)H(11)FO(3)S, was prepared by alkaline hydrolysis of ethyl 2–(3–ethyl­sulfan­yl–5–fluoro–1–benzofuran–2–­yl) acetate. In the crystal structure, the carboxyl groups are involved in inter­molecular O—H⋯O hydrogen bonds, which link the mol­ecules into centrosymmetric dimers. These dimers are further packed into stacks along the b axis by aromatic π–π inter­actions between the furan ring and the benzene ring of neighbouring benzofuran ring systems [centroid–centroid distance = 3.684 (5) Å].