The synthesis and characterization of main chain liquid crystalline polyesters arising from 2,5-bispentyloxy substituted terephthalic acid (3) and aromatic diols are described. 3 was prepared from diethyl 2,5-dihydroxyterephthalate and 1-bromopentane. The polyesters were prepared from 4,4’-dihydroxybiphenyl (5), hydroquinone (6), 2,5-dimethyl hydroquinone (8) and the substituted terephthaloyl dichloride (4) in 1,1,2,2-terachloroethane. Their structures were characterized by H-1-NMR, GPC and elemental analyses; their thermal behavior was studied by DSC measurements, microscopy under polarized light, and thermogravimetric analyses. The melting points are in the range of 130-280-degrees-C. All of them except of those with a high amount of 2,5-dimethyl hydroquinone (8) form a nematic phase above their melting point.