The mol-ecule of the title compound, C(18)H(10)O(4), is centrosymmetric and planar. A long phenolic O-H bond is observed [1.19 (9) Å], which is involved in an intra-molecular hydrogen bond between the phenolic and quinonoid O atoms. The mol-ecules pack in a herringbone pattern and are linked to each other via inter-molecular C-H⋯O hydrogen bonds (2.73-2.77 Å).