The stabilities, optimized molecular geometries, APT charges and vibrational characteristics for the nicotinic acid (NA) and 2-fluoronicotinic acid (2-FNA) have been studied theoretically using density functional theory (DFT) methods. The E (trans) conformers of nicotinic acid are found to be more stable and less polar than their respective Z (cis) conformers. Most of the vibrational frequencies have nearly the same magnitude for the NA and 2-FNA molecules; however, significant changes are noticed in their IR intensities, Raman activities and depolarization ratios of the Raman bands.