Dielectric properties of the mixture of two thioester compounds: 4-8-alkoxybenzoate-thiocarboxyl S-4-pentylphenyl (8OS5), (s)-4-(1-methylheptyloxy)biphenyl-4-thiocarboksyl 4-9-alkilphenyl (MHOBS9) are presented. The chiral compound exhibits nematic (N * ) and ferroelectric smectic C * phase (SmC * ). The achiral compound shows N, SmA and monotropic SmC and SmB phases. the mixture of both compounds of 0.5 molar fraction shows SmC * in the wider temperature range than pure MHOBS9. The mixture was studied using frequency domain dielectric spectroscopy. Dielectric measurements for the SmC * phase of the mixture revealed Goldstone mode at higher frequencies and Maxwell-Wagner relaxation at low frequencies.