3-(4-Biphenyl-1-yl)-3-hydr-oxy-1-phenyl-prop-2-en-1-one.

In the title compound, C(21)H(16)O(2), the six crystallographically independent mol-ecules (Z' = 6) all exist in the enolized form. Strong intra-molecular hydrogen bonds are observed: one approximate H-atom-centered O⋯H⋯O hydrogen bond, two tautomeric forms O-H⋯O (three mol-ecules) and O⋯H-O (two mol-ecules). Only one weak inter-molecular C-H⋯O hydrogen bond between two neighboring mol-ecules is observed in the crystal structure. In addition, eight very weak non-conventional inter-molecular C-H⋯π hydrogen-bonding contacts between mol-ecules are observed.