In the title molecule, C21H16O2, the naphthalene ring system is planar
and the dihydronaphthalene ring is distorted from planarity. The dihy
drobenzene ring adopts a flattened-boat conformation. The dihedral ang
le between the naphthalene and dihydronaphthalene ring systems is 64.1
3 (5)degrees. The hydroxyl and carbonyl O atoms are involved in O-H ..
. O intramolecular hydrogen bonding.