The coexistence curves and light scattering data for a critical solution of (benzonitrile + octane) have been reported. The critical exponents relating to the difference in the density variables between two coexisting phases beta, the osmotic compressibility gamma, and the correlation length v, have been deduced and the values are consistent with the 3D-Ising value in the range close to the critical point. The experimental results of the coexistence curves have also been analyzed to examine the Wegner correction terms and the behavior of the diameter of the coexistence curves. The light scattering data are well described by the crossover model proposed by Anisimov and Sengers, and show a monotonic crossover of the critical exponents gamma and v from its 3D-Ising value to the mean-field value as the temperature departures from the critical point. Furthermore, the dependences of the critical amplitudes on the mass of n-alkane for the binary solutions of (benzonitrile + n-alkane) have been discussed. (C) 2008 Elsevier Ltd. All rights reserved.