In this study, a new series of semiflexible liquid crystalline (LC) polyesters and poly(ester-amide)s were synthesized and characterized. Polymers based on 4-hydroxybenzoic acid (4-HBA), 6-hydroxy-2-naphthoic acid (HNA), suberic acid (SUA), and sebacic acid (SEA) were modified with hydroquinone (HQ) and different concentrations of 4-acetamidophenol (AP) to obtain a polyester and two poly(ester-amide)s, respectively. All polymers were successfully prepared using conventional melt-condensation techniques. The polymers were characterized by inherent viscosity measurements, SEC, hot-stage polarizing microscopy, DSC, and TGA. The mechanical behavior was investigated using DMTA and tensile testing. All linear polymers have T,s in the range of 50-80 degrees C and melt between 120 and 150 degrees C. Our polymers display good thermooxidative stabilities (5% wt loss at similar to 400 degrees C) and exhibit homogeneous nematic melt behavior over a wide temperature range (Delta N similar to 250 degrees C). The liquid crystal phase was lost when high concentrations of nonlinear monomers such as 3-HBA (>27 mol %) and resorcinol (RC) (>23 mol %) were incorporated. The LC polyester based on 4-HBAIHNA/HQ/SUA/SEA could easily be processed into good quality films and fibers. The films display good mechanical properties (E' similar to 4 GPa) and high toughness, that is, similar to 15% elongation at break, at room temperature. (C) 2008 Wiley Periodicals, Inc.