Perfluoro(2,3-diphenylbutane-2,3-diol), CF3(C6F5)C(OH)C(OH)(C6F5)CF3, prepared by the reductive dimerization of C6F5COCF3, has been separated into meso- and DL-isomers and the latter resolved via its cinchonidine salt into optical enantiomers. The doubly ionized diol, PDBD2−, acts as a dinegative, chelating, ligand, and neutral complexes of the form (PDBD)-ML2 may be isolated, where L is a neutral nitrogen- or phosphorus-containing ligand and M = Ni2+ or Cu2+. Use of the resolved diol enables optically active metal complexes to be prepared, and from their o.r.d./c.d. spectra we assign an absolute configuration to the diol. The partially fluorinated diols CF3(C6H5)C(OH)C(OH)(C6H5)CF3 and CH3(C6F5)C(OH)C(OH)(C6F5)CH3 have also been prepared from the appropriate ketones. The former, which appears to be exclusively the meso-isomer, has more limited chelating ability than the fully fluorinated analog, while the latter shows no ligand properties; these differences are ascribed to the reduced acidity resulting from the lower degree of fluorination.Nuclear magnetic resonance studies suggest hindered rotation of the C6F5 groups through steric interaction with CF3 groups in perfluoro(2,3-diphenylbutane-2,3-diol); an alternate explanation involving hydrogen bonding from the hydroxylic proton to aromatic fluorine atoms is considered less likely.