Fast hydrolysable polyesters are promising candidates as biodegradable plastics degrading to carbon dioxide, water, and biomass in the presence of oxygen in a suitable environment. Polyesters with a balance of good mechanical properties and fast hydrolysable are urgently needed as a sustainable solution to the problem of plastic pollution. In this work an aromatic polyester, a constitutional isomer of PBT [poly(1,4-benzenedimethylene succinate) (PBDMS)], and its copolymers in which aliphatic ester units balance the mechanical, thermal, and hydrolysis properties. ). The selected polyester (PB₆₄BDM₃₆S) was completely degraded in industrial compost using the method prescribed in DIN EN ISO 20200 in less than 5 weeks. The films of these polyesters showed much faster hydrolysis under basic conditions, making them promising for further detailed degradation studies under different environmental conditions.