In the crystal structure of the title compound, C22H14O6··2C2H6OS, 4,6-dibenzoylisophthalic acid is connected to two dimethyl sulfoxide molecules by strong O—H...O=S hydrogen bonds. Weak intermolecular C—H...O hydrogen bonds connect molecules into dimers. Intramolecular three-centred C—H...O hydrogen bonding is favoured by a syn conformation of both carboxyl groups. The two dimethyl sulfoxide molecules were found to be disordered over two equally populated sites.