The temperature dependence of the dielectric properties of two thermotropic liquid crystalline mesogens has been investigated to provide a comparison of the OC6H13 and isothiocyanato (-NCS) groups. A comparative study of the variation of dielectric permittivities of the two compounds has been made and the effective molecular dipole moment mu(eff) determined as a function of temperature. From the present study and previous optical studies [1], a comparison of the temperature variation of the angle of inclination beta of the molecular dipole moment with the director for both mesogens could be determined and compared. In order to determine the nature of the molecular association in the mesophase, the molecular correlation factors (g) have been estimated from measurements of dipole moments of the compounds in solution.