Two experimental techniques—time domain spectroscopy (TDS) and a steady state frequency method—have been used to study dielectric spectra for the isotropic, nematic, SA, SCand SYphases of two thioesters (4-n-pentylphenyl-4′-n-octyloxy-and 4′-n-nonyloxythiobenzoates (CnH2n+1O‒C6H4‒COS‒C6H4‒C5H11, wheren= 8 andn= 9) known as8S5 and9S5, in the frequency range from 10 Hz to 10 GHz. In the case of8S5 a deuteriated sample (8S5-d28) has been used to study relaxation processes in the nematic and smectic phases.