The title compound, C(19)H(20)O(3), was obtained from 1,4-bis-(4-methyl-phen-yl)but-3-yn-2-one in the presence of carbon monoxide by Ni(CN)(2) catalysis in a basic aqueous medium. Inter-molecular O-H⋯O hydrogen bonds lead to the formation of hydrogen-bonded carb-oxy-lic acid dimers [graph-set motif R(2) (2)(8)]. Weak C-H⋯O hydrogen bonds between neighbouring dimers further extend the structure to give rise to a three-dimensional supra-molecular network.