7-Chloro-4-oxo-4H-chromene-3-carbaldehyde

In the title compound, C10H5ClO3, a chlorinated 3-formyl-chromone derivative, all atoms are essentially coplanar (r.m.s. deviation = 0.0592 Å for all non-H atoms), with the largest deviation from the least-squares plane [0.1792 (19) Å] being for the chromone-ring carbonyl O atom. In the crystal, mol-ecules are linked through C-H⋯O hydrogen bonds to form tetrads, which are assembled by stacking inter-actions [centroid-centroid distance between the pyran rings = 3.823 (3) Å] and van der Waals contacts between the Cl atoms [Cl⋯Cl = 3.4483 (16) Å and C-Cl⋯Cl = 171.73 (7)°] into a three-dimensional architecture.