The title compound, C14H10O, crystallized in the centrosymmetric space group P21/c with a single molecule in the asymmetric unit. The C-HO interaction having the shortest CO distance involves the ring-bridging atom C9 and one of its H atoms and results in the formation of a cyclic dimer about a center of symmetry. The molecular core is nearly planar. The dihedral angle between the best-fit plane of the ring to which the aldehyde group is attached and the plane of the aldehyde group is 4.4 (9)°. In a number of respects the molecular disposition is similar to that previously determined for the geometrically similar dibenzofuran-4-carboxaldehyde molecule.