2-Cyano-3-(4-hydroxy­phenyl)acrylic acid

The title compound, C₁₀H₇NO₃, has an almost planar molecule, forming hydrogen-bonded dimers via the carboxyl groups. These dimers are further connected by hydrogen bonds between the hydroxy groups of the benzene rings and the cyano N atoms into ribbons, which are arranged in layers. The H atom of the carboxyl group is disordered over two sites.