Abstract: Provided is a liquid crystalline polymer which is obtained by copolymerizing at least one polyfunctional aromatic monomer selected from the group consisting of the compounds represented by the formulae (I), (II) and (III) below with at least one polymerizable monomer. The liquid crystalline polymer of the present invention is excellent in heat resistance, molding properties, flow properties and mechanical properties, especially it provide molded article with improved weld strength.

Abstract: A melt-processable copolyester composed of the following structural units (I), (II) and (III) and/or (IV) as main structural components, whereinunit (I) is represented by the formula ##STR1## wherein X.sub.1, X.sub.2, X.sub.3 and X.sub.4, independently from each other, represent H, F, Cl, Br, CH.sub.3 or C(CH.sub.3).sub.3, provided that X.sub.1 to X.sub.4 do not simultaneously represent H, and n is 2 or 4,unit (II) is at least one unit selected from the group consisting of ##STR2## wherein at least one of the hydrogen atoms in each aromatic ring in units (II), (III) and (IV) may be substituted by an alkyl or alkoxy group having 1 to 4 carbon atoms or a halogen atom.The proportion of unit (I) is 2.5 to 35 mole %, the proportion of unit (II) is 2.5 to 35 mole %, and the proportion of unit (III), (IV) or a combination of units (III) and (IV) is 30 to 95 mole %.