Ultraviolet (UV) absorption of some nematic liquid crystals (LCs) with different conjugation length was investigated under polar and nonpolar diluted solutions, vapor phase, nematic phase, and isotropic phase. Results of the vapor phase and nonpolar solution are very similar. For nonpolar LC molecules, little red shift is observed. For polar molecules, the icelectron resonant wavelength exhibits a significant red shift in the nematic phase when compared with the results measured in solvents or vapor phase. Short range intermolecular interaction is thought to be responsible for the observed red shift.