It is intended to provide a liquid crystalline polyester whose orientation in the state of liquid crystal can be easily immobilized as glass phase and which is suitable for application to optical elements.A liquid crystalline polyester comprising repeating units a, b, c and d represented by the following general formulae: ##STR1## where X and Y are each independently a hydrogen atom, Cl, Br or an alkyl group having 1 to 4 carbon atoms, the repeating units a, b, c and d being in mole ratios such that (a+b)/(c+d) is approximately 1, a/b is in the range from 98/2 to 50/50 and c/d is in the range from 70/30 to 10/90.