TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The bivalent aliphatic hydrocarbon-containing compound (II) is preferably chosen from ethane-1,2-diol, butane-1,3-diol, heptane-1,7-diol, cyclohexane-1,4-diol, 1-(2-hydroxypropoxy)propan-2-ol, 2-(2-(2-hydroxypropoxy)propoxy)propan-1-ol, 2-((2-hydroxyethyl)(methyl)amino)ethan-1-ol, (4-(hydroxymethyl)cyclohexyl)methanol and 2-(4-(hydroxymethyl)cyclohexyl)ethan-1-ol.    TECHNOLOGY FOCUS - POLYMERS - Preparation (claimed): The polyester compound is prepared by reacting 1,3-benzoxazole derivative (I) and bivalent aliphatic hydrocarbon-containing compound in molar ratio of 10/1-1/10.    TECHNOLOGY FOCUS - POLYMERS - Preferred Process: The polyester compound is further obtained by reacting 1,3-benzoxazole derivative (I), bivalent aliphatic hydrocarbon-containing compound (II) and aromatic dicarboxylic acid, its salt, ester and halide. 1,3-Benzoxazole derivative (I) and bivalent aliphatic hydrocarbon-containing compound (II) are reacted at -10 degrees C to 200 degrees C. Preferred Composition: The polyester compound is preferably of formula (II)-(V). Preferred Properties: The polyester compound has intermediate-glass transition point (Tmg) of 80 degrees C-300 degrees C, melting point (Tm) of 140-500 degrees C and 5 %mass weight reduction temperature (Td) of 250-500 degrees C. Preferred Definitions:    Xdc=phenylene, naphthylene, anthracenylene, furandiyl, pyridinediyl, thiophenediyl or quinolinediyl (all optionally substituted);and    ndc=0.    EXAMPLE - 1.89 mL 9.18 mmol Diphenylchlorophosphonate was dissolved in 20 mL pyridine, 0.164 mL 2.12 mmol dimethylformamide was added and stirred at room temperature for 30 minutes. Then, 3.53 mmol 2-(4-carboxyphenyl)benzo(d)oxazole 5-carboxylic acid was added to the resultant product, stirred at room temperature for 10 minutes, heated at 120 degrees C, 3.53 mmol ethylene glycol was added and stirred at 120 degrees C for 12 hours. The resultant mixture was thrown into 10 times volume methanol, cooled to room temperature and filtered, to obtain light brown solid. The resultant solid was washed using 100 mL boiling methanol and filtered, to obtain light brown solid. The obtained solid was dried under reduced pressure at 50 degrees C, to obtain 1.03 g polyester compound with yield of 94%.