3-Acetyl-4-hy-droxy-6,7-dimethyl-2H-chromen-2-one.

In the title coumarin derivative, C(13)H(12)O(4), the 2H-chromene ring system is essentially planar [maximum deviation = 0.047†(1)†à ]. An intra-molecular hydrogen bond is observed between the hy-droxy and the ketonic O atoms. In the crystal, pairs of inter-molecular C-H⋯O hydrogen bonds link inversion-related mol-ecules into dimers. Additional inter-molecular C-H⋯O hydrogen bonds further inter-connect these dimers into two-dimensional arrays incorporating R(2) (2)(9) ring motifs.