The physical properties of a binary liquid crystal system were investigated, namely the transition temperatures, birefringence and viscoelastic constants measured by using thermal optical microscopy, differential scanning calorimetry and light scattering techniques with coherent laser light beams. These properties were sometimes found to exhibit linear dependence on the mole fractions of the components. Our results indicate that a required property is obtainable by the regulation of the molar ratio as if the length of the alkyl chain connected with a cyanobiphenyl core group were variable; i.e. the apparent chain length could be controlled.