Activity coefficients at infinite dilution, gamma(13)(infinity), for both polar and non-polar solutes in the polar solvent quinoline, or 1,3-dimethyl-2-imidazolidinone have been determined by gas-liquid chromatography at T = (278.15, 313.15, and 323.15) K. This work is a continuation of our programme of measurements of gamma(13)(infinity) The results have been used to predict the solvent potential for separation of liquids by extractive distillation. Gas-liquid chromatography is a well-established and accurate method for obtaining gamma(13)(infinity). The mixed second virial coefficients, B-12, used in this work were deter-mined by the principle of corresponding states and the McGlashan-Potter equation. The Hudson and McCoubrey combining rules and the Lorentz rule were used for the calculations of T-12(c) and V-12(c), respectively.