2-Hy-droxy-4-(prop-2-yn-yloxy)benz-alde-hyde.

The asymmetric unit of the title compound, C10H8O3, contains two independent mol-ecules, both of which are almost planar (r.m.s deviations for all non-H atoms of 0.044 and 0.053 Å). The dihedral angles between the benzene ring and the prop-1-yne group are 3.47 (1) and 3.07 (1)° in the two mol-ecules, and the prop-1-yne groups adopt extended conformations. In each mol-ecule, an intra-molecular O-H⋯O hydrogen bond involving the OH and aldehyde substituents forms an S(6) ring. In the crystal, mol-ecules are linked into cyclic centrosymmetric dimers via C-H⋯O hydrogen bonds, generating R2(2)(14) ring motifs. The crystal structure is further stabilized by aromatic π-π stacking inter-actions between the benzene rings [centroid-centroid distances = 3.813 (2) and 3.843 (2) Å].