We have presented a novel vertical alignment method simultaneously enhancing the alignment ability and electro-optical performances of nematic liquid crystals (LCs). The method relies on the self-assembly of 4-(4-heptylphenyl) benzoic acid and 2-carboxyethyl acrylate through hydrogen bonding with conventional polyimide and the generation of pre-tilting in the LC molecules using ultraviolet irradiation under applied voltage. The electro-optical measurements of a LC device fabricated by using this self-assembled polyimide layer exhibited strong homeotropic alignment and fast response time. The proposed alignment method may be valuable in providing new functional alignment materials for high-performance LC devices.