Bicomponent mixtures of esters (4-cyanobiphenylyl-4’ 4’-alkyl-biphenylcarboxylate-4 (nCBB) or 4-cyanobiphenylyl-4’ 4-alkylbenzoate (nBCB) with 4-cyanophenyl 4-alkylbenzoate (n. CN)) were studied by the thermomicroscopic method and their phase diagrams were established. The strong enhancement of a smectic A(d) phase in mixtures with the smectic members of n.CN (n > 9) and the induction of a smectic A(d) phase in a shape of an island surrounded by a nematic phase in mixtures with the nematic members of nCB (n less than or equal to 9) were observed. The influence of the aliphatic chain length on the observed phenomenon was discussed. The temperatures of transitions from the virtual A(d) to the nematic phase for pure nCBB and nBCB were estimated.