Abstract Ten 4, 4'-disubstituted bis (arenesulfon) imides of the general formula XC 6 H 4 SO 2 NHSO 2 C 6 H 4 X have been synthesized and their structures confirmed by their 1 H NMR spectra. Elemental analyses are presented for the compounds not yet described. The dissociation constants of these model substances have been measured potentiometrically in pyridine, dimethylformamide, methanol, ethanol, propylene carbonate, acetone, ...