In the present work, we have analyzed the molecular interactions existing in a 4-n-pentyl-4-cyano-biphenyl (5CB) monomer and its dimer, in the head-tail configuration. The optimized geometrical structures of the monomer and dimer were obtained using the theoretical level wB97-XD/6-311G++(d,p). The intermolecular interactions were analyzed through the non-covalent interaction index (NCI) and the localized molecular orbital energy decomposition analysis method (LMO-EDA). Our results suggest that the antiparallel alignment of the 5CB liquid crystal is caused by attractive contributions arising from the intermolecular interactions between the aromatic rings. Furthermore, these interactions were found to cause deformations in the geometries of the monomers forming the dimer.