Specific retention volumes, activity coefficients at infinite dilution, partial molar excess free energies, partial molar excess enthalpies and entropies, partial molar enthalpies and entropies of solution for m-, p-, o-xylenes and m-, p-, o-ethyltoluenes in 3,4'-dimethyl-4-[(4-chlorobenzyl)oxy] azobenzene (DMCBOA) as solvent were determined. The separation of m-, p-, o-xylenes and m-, p-, o-ethyltoluenes was studied on a packed column with 2.5% DMCBOA on Chromosorb W HP 100-120 mesh. The synthesis of this liquid crystal is presented. At cooling, starting from isotropic liquid (129.5 degrees C) a nematic phase of DMCBOA was identified in the range of 109.6-103.6 degrees C, but m-, p-, o-xylenes and m-, p-, o-ethyltoluenes were separated at temperature ranges 65-48 degrees C and 90-55 degrees C, respectively.