Two new thermotropic, liquid crystalline (LC) hyperbranched polyesters with carboxylic acid end groups were synthesized by direct polycondensation of two pseudo AB(2) type monomers, 2-[(10-(4-hydroxyphenoxy)decyl)oxy]terephthalic acid and 2-[(10-((4＇-hydroxy-1,1＇-biphenyl-4-yl)oxy)decyl)oxyl]-terephthalic acid. Their LC properties were characterized by DSC and optical microscopy. The carboxylic acid groups of the polyesters were converted to the corresponding methyl esters, and their properties were also investigated. The number average molar masses of the polymers were 7000 and 15 000, respectively, corresponding to average degrees of polymerization of about 17 and 31. The degrees of branching of the polymers determined by C-13 NMR spectroscopy were 37 +/- 10% and 43 +/- 10%, respectively. The polyesters with the carboxylic acid end groups form the nematic phase above their glass transition temperatures (T-g), whereas their methyl ester counterparts are not liquid crystalline. This observation indicates that the formation of hydrogen bonds between the carboxylic acid terminals plays an important role in mesophase formation by the present polyesters. All the polymers are amorphous and are soluble in common organic solvents such as THF, DMF, NMP, pyridine, and DMSO. The T-g values of the methyl ester polymers are substantially lower than those of the polymers having acid terminals.