2,2'-[(4-But-oxy-phen-yl)methyl-ene]bis-(3-hy-droxy-5,5-di-methyl-cyclo-hex-2-en-1-one).

In the title compound, C27H36O5, the dihedral angles between the planes of the benzene ring and the cyclo-hexenone rings are 60.87 (10) and 65.04 (10)°, while the dihedral angle between the mean planes of the two cyclo-hexenone rings is 39.33 (10)°. Each cyclo-hexenone ring has a carbon atom bonded to two methyl groups, which acts as the flap atom, resulting in an envelope conformation. The opposite orientation of the hy-droxy and carbonyl oxygen atoms allows for the formation of two intra-molecular O-H⋯O hydrogen bonds and C-H⋯π (ring) inter-actions also help to establish the molecular conformation.