The isothermal crystallization kinetics of 4-n-pentyl-4-cyanobiphenyl (5CB) has been studied with Differential Scanning Calorimetry (DSC) and Dielectric Relaxation Spectroscopy (DRS). 5CB is a well characterized material which makes it ideal for a dielectric and thermal comparative study. The effect that isothermal crystallization exerts on the behavior of relaxation processes alpha and delta by cooling the isotropic liquid below the nematic phase or through the process of cold crystallization by heating it from the supercooled state is explored by comparing the DRS and DSC. Furthermore, by employing the Avrami equation, we compare the ability to probe the crystallization with each technique.