The title compound, C(20)H(16)O(6), which contains one chiral centre, crystallizes as a racemate. The mean planes of the two coumarin units make a dihedral angle of 88.07 (2)°. The pyrone ring containing the chiral centre adopts a sofa conformation. In the crystal, four mol-ecules are linked by O-H⋯O hydrogen bonds, forming a tetrameric ring with graph-set motif R(4) (4)(32). These tetramers are further linked by O-H⋯O hydrogen bonds into a three-dimensional network.