Electron paramagnetic resonance studies, using PD-Tempone as a probe, on the n-hexyl and n-heptyl members of the p-cyanophenyl p-(n alkyl)benzoate (RCBz) liquid crystals confirm the previously observed directions of the discontinuities in the a and g-factor values on solidification and on melting of the 6CB liquid crystal. Careful analysis of an unusual variation in the g-factor value on cooling and heating in the vicinity of the nematic-to-isotropic transition points to the existence of molecular change alongside the bulk change. Evidence for such changes is provided by the results of differential scanning calorimetry (DSC) measurements and ab initio calculations using the STO-3G basis set. DSC endothermic peaks on cooling (or exothermic peaks on heating) that are independent of cooling (or heating) rates reflect a conformational change. DSC also shows the existence of polymorphic solid that, on heating, undergoes a series of rate-dependent solid-solid modifications until the most stable solid form is reached. The STO-3G ab initio calculations suggest three possible conformers for these liquid crystals.