1,5-Pentanediol (PeDO) is a biobased but less studied diol monomer for polyester synthesis. As one of a series of studies on PeDO-derived polyesters, two aliphatic-aromatic copolyesters, poly(pentylene succinate- co -terephthalate) (PPeST) and poly(pentylene adipate- co -terephthalate) (PPeAT), were synthesized through melt copolycondensation of biobased PeDO, SA (or AA) and TPA. The chemical structure was characterized by 1H NMR, and the thermo-mechanical properties were assessed by DSC, WAXD, TGA and tensile test. The 1H NMR results demonstrated random structure and controllable copolymer composition. PPeATs showed two-stage thermal decomposition as the PeA units were clearly less stable than the PeT units at high temperature. In comparison, PPeSTs exhibited better thermal stability which was improved with increasing PeT unit content. Due to the difference in thermal stability, high intrinsic viscosity (0.78–1.4 dL/g) was facilely reached in synthesizing PPeSTs with melt copolycondensation, but medium intrinsic viscosity (0.58–0.66 dL/g) for PPeATs. Both kinds of copolyesters showed isodimorphism behavior and composition-dependent weak crystallizability. The PeT-rich copolyesters like PPeST 85 and PPeAT 85 showed reasonably good tensile properties because of higher crystallizability and stronger chain interaction. • PPeST & PPeAT copolyesters with controllable copolymer composition were synthesized and characterized for the first time. • PPeATs are less thermally stable and show two-stage thermal decomposition due to poor thermal stability of the PeA units. • PPeSTs and PPeATs show isodimorphism behavior and composition-dependent weak crystallizability. • PeT-rich copolyesters possess reasonably good tensile properties. [ABSTRACT FROM AUTHOR]