Dielectric properties and relaxation processes of binary mixture (MIX I) and quaternary mixture (MIX II), both composed of 4-alkylphenylcarbonyloxy-4’-cyanophenyls and -4’-cyanobisphenyls, have been studied by dielectric spectroscopy in the frequency range from 5 Hz to 10 CI-ia. Dielectric measurements have been done for two principal alignments of the N, SmA(d) and N-R phased, In the case of MIX II the parallel component of dielectric permittivity shows a pronounced decrease in the Sm A(d) phase due to dipole-dipole correlation, This anomaly is much weaker for MIX I, Low frequency spectra for both mixtures consist of two well separated absorption peaks connected, respectively, with biphenyl and triphenyl ring entities, By fitting a sum of two Cole-Cole functions it was possible to compute dielectric parameters of the relaxation processes observed. In both cases the relaxation times exhibit Arrhenius type behavior with activation energy higher in tile N-R than in SmA(d) and N phases. At high frequencies (from 10MHz to 10GHz) a broad spectrum, originating from a number of relaxation processes, have been observed.