Abstract
Phase diagrams of binary mixtures made up of smectics A: 120CB and a compound from the n-DBT homologous series are described. It has been found that when the smectic layer spacing ratio of the components of d120CBdn-DBT = 1.53 is exceeded a nematic phase is created in the mixture, and for d120CBdn-DBT ≥ 1.83 the smectic regions become separated by a nematic gap. The virtual nematic properties of the compounds are revealed due to the weakening of the intermolecular attractive forces in the smectic layers.