The title compound, C(16)H(14)O(5), is a triclinic polymorph of a previously reported monoclinic structure [Hosseinzadeh et al. (2011 ▶). Acta Cryst. E67, o1544]. The mol-ecule is roughly planar, the r.m.s. deviation from the least-squares plane of all non-H atoms being 0.092 Å. In the crystal, adjacent mol-ecules are linked through C-H⋯O hydrogen bonds into an infinite two-dimensional network parallel to (011). The layers are further connected via C-H⋯π inter-actions, forming a three-dimensional structure. Intra-molecular O-H⋯O and C-H⋯O hydrogen bonds are also observed.