4,4′-Dimeth­oxybi­phenyl-3,3′-di­car­box­ylic acid

The title compound, C₁₆H₁₄O₆, was recrystallized under solvothermal conditions. The mol­ecules are located on inversion centres, with one complete mol­ecule generated from the asymmetric unit by inversion. There are intra­molecular O—H...O hydrogen bonds involving the carb­oxy­lic acid group and the O atom of the adjacent meth­oxy group. In the crystal, mol­ecules are linked via O—H...O hydrogen bonds, forming chains propagating along [100]. The chains are linked via C—H...O hydrogen bonds, forming sheets parallel to (001).