Relative permittivities (epsilon), densities (rho), and refractive indices (n(D)) were measured for binary mixtures of sulfolane with ethylene glycol, diethylene glycol, poly(ethylene glycol) with an average molecular weight of 200, and poly(ethylene glycol) with an average molecular weight of 600 at 303.15 K over the whole mole fraction range. From these experimental data, the excess molar volumes (V-E), and deviations in refractive indices (Deltan(D)), relative permittivities (Deltaepsilon), and molar polarization (DeltaP(m)) were calculated. These quantities were fitted to the Redlich-Kister polynomial equation to derive the binary adjustable parameters and standard errors.