(3-Chloro-phen-yl){2-eth-oxy-5-[(Z)-hydroxy(phen-yl)methyl-idene]cyclo-penta-1,3-dien-1-yl}methanone.

The title compound, C(21)H(17)ClO(3), which crystallizes as one of two possible oxo/hy-droxy-fulvene prototropic tautomers, possesses a strong intra-molecular O-H⋯O hydrogen bond that closes a seven-membered ring. The dihedral angles between the central five-membered ring and two pendant rings are 55.05 (9) and 44.51 (10)°. The crystal packing is characterized by weak inter-molecular C-H⋯O inter-actions between an H atom of the oxymethyl-ene unit and the carbonyl group of an adjacent mol-ecule, resulting in formation of chains of mol-ecules along the a axis.