Abstract: An anthraquinone compound represented by formula: ##STR1## wherein R and X are as defined in the specification, and a polarizing film containing the same. The anthraquinone compound exhibits satisfactory compatibility with organic polymers and high dichroism, and the polarizing films have excellent performance characteristics.

Abstract: A polarizing film which comprises a film base having thereon an anthraquinone dye of general formula (I): ##STR1## wherein R.sup.1 and R.sup.2 each represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyloxy group, an aryl group, a cyclohexyl group, a 4-alkylcyclohexyl group, a carboxylic acid ester group, a carboxylic acid amide group, a halogen atom, ##STR2## X represents an oxygen atom, a sulfur atom or an amino group.

Abstract: An anthraquinone compound represented by formula: ##STR1## wherein R and X are as defined in the specification, and a polarizing film containing the same. The anthraquinone compound exhibits satisfactory compatibility with organic polymers and high dichroism, and the polarizing films have excellent performance characteristics.

Abstract: A process for producing a copolymeric polyester, which comprises a first step of preparing a copolymeric oligomer by reacting a starting material oligoester or polyester having repeating units of the formula: ##STR1## wherein R.sub.1 is a divalent aromatic hydrocarbon group having from 6 to 10 carbon atoms, a divalent alicyclic hydrocarbon group having from 4 to 20 carbon atoms or/and a divalent aliphatic hydrocarbon group having from 1 to 40 carbon atoms (provided a hydrogen atom in the aromatic ring of the aromatic hydrocarbon group may be substituted by a halogen atom or an alkyl or alkoxy group having from 1 to 4 carbon atoms), and R.sup.