Results of the phase transition and the static and dynamic dielectric investigations of several new liquid crystalline compounds, consisting of three phenyl rings with the alkyl and isothiocyanato terminals, fluoro lateral substituents, and different bridging groups, are presented. These compounds form the nematic phase accompanied in some cases by a smectic phase. The dielectric parameters are analysed in relation to the dipole structures of the molecules. In the nematic phase some compounds with a bridging carboxylic group exhibit the crossover of the principal permittivity components within the megahertz frequency range.