Two complementary dielectric techniques, broadband dielectric relaxation spectroscopy (DRS) and thermally stimulated depolarization currents (TSDC), covering together broad ranges of frequency and temperature, were employed to study molecular mobility in the molecular liquid crystal 5CB. Three relaxations were observed and analyzed with respect to time scale, strength and shape, a sub-glass beta relaxation and the alpha and delta relaxations in the supercooled nematic phase. In addition, TSDC and isochronal DRS measurements were used to follow phase transitions in 5CB and CE8 in comparison with DSC. The results demonstrate the power of dielectric techniques, in particular TSDC, for monitoring phase transitions in liquid crystals.