The binary mixtures of polar compounds where one component is 4-cyanobiphenyl-4’-yl 4’-heptylbiphenyl-4-carboxylate (7CBB) and another one is a cyano derivative with the same alkyl chain length and different core structure were tested. Their phase diagrams obtained by thermomicroscopy are presented. The induced Ad phase appears in all presented mixtures. Molecules with short cores and with low lateral interactions cause the strongest induction of the A(d) phase.