5,6-Dimethyl-1,2,9,10-tetra­hydro­pyrano[3,2-f]chromene-3,8-dione

The title mol­ecule, C(14)H(14)O(4), lies on a twofold rotation axis that bis­ects the central benzene ring, with only one half-mol­ecule in the asymmetric unit. The pyran­one systems adopt distorted twist- boat conformations, with the two methyl­ene C atoms displaced by 0.537 (1) and 0.163 (2) Å from the best-fit plane through the remaining five C and O atoms (r.m.s. deviation = 0.073 Å). In the crystal, bifurcated C—H⋯(O,O) hydrogen bonds link pairs of adjacent mol­ecules in an obverse fashion, stacking mol­ecules along c. These contacts are further stabilized by very weak π–π inter­actions between adjacent benzene rings with centroid–centroid distances of 4.1951 (4) Å. Additional C—H⋯O contacts link these stacks, giving a three-dimensional network.