Compound, polymer, liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

The invention provides a compound, a polymer, a liquid crystal aligning agent, a liquid crystal alignment film and a display device. The liquid crystal aligning agent can be used for forming the liquid crystal alignment film characterized by less decrease of voltage holding ration in long-term use and excellent reliability. The liquid crystal aligning agent contains the polymer with the structure described in the formula (I). In the formula (I) of *-X1-(CR12)m1-Y-(CR12)m2-X2-*(1), X1 and X2 are single bonds, oxygen atoms, sulphur atoms, carbonyl or ester bonds and cannot be single bonds both; Y is groups obtained by subtracting 2 hydrogen atoms from 5-membered ring or 6-membered ring aromatic compounds; the aromatic compounds contain one or two heteroatoms containing more than one of nitrogen atoms, oxygen atoms and sulphur atoms; R1 with a number greater than 1 is hydrogen atoms or fluorine atoms; m1 and m2 are integers ranging from 0-20; * represents combination bonds.