The data obtained from both in vitro assays identified bisphenols p,p'-3 and p,p'-5 as exhibiting minimal to no estrogenic activity. Among these, bisphenol p,p'-3 could be accessed with significantly higher yield and regioselectivity relative to p,p'-5, thereby, the former was selected for scaled-up synthesis and subsequent incorporation into a polymer matrix. The scaled-up synthesis was performed under modified conditions in order to reduce the amount of excess reagents and lower the catalyst loading, delivering the desired bisphenol 3 in high yield (72%), but as a mixture of regioisomers (p,p'/m,p'-3 7.5:1). Notably, previous reports indicated that the minor m,p'-3 regioisomer displays even lower estrogenic activity compared to p,p'-3, 14d thus the regioisomeric mixture 3 was used for polymer synthesis without further separation. While bisphenol 3 was previously incorporated into polycarbonate and epoxy resins, in this work we sought to incorporate 3 into a polyester, as this class of polymers is more attractive from the sustainability and circular material flow perspectives. To overcome the lower reactivity of phenolic alcohol groups for polycondensation, bisphenol 3 was first functionalized as bisglycol ether derivative 3-G with ethylene carbonate (Figure ). A bisglycolated BPA derivative BPA-G was synthesized using the same procedure for comparison. The bisglycolated bisphenols were each polymerized by reaction with dimethyl succinate (DMS)a potentially biobased aliphatic diesterto furnish two polyester materials, 3-G-DMS and BPA-G-DMS. The number and weight average molar masses (M ̅ n and M ̅ w, respectively) and dispersities (Đ) of the purified materials were determined by sizeexclusion chromatography (SEC) analysis, displaying higher molar masses and dispersity for 3-G-DMS relative to BPA-G-DMS (M ̅ n = 21.7 vs. 15.2 kDa, M ̅ w = 92.1 vs. 33.2 kDa and Ð = 4.2 vs. 2.2). The higher M ̅ n, M ̅ w, and Ð values for 3-G-DMS presumably stem from the higher flexibility of 3-G monomer, which bears no substituents at the bridging methylene carbon, unlike BPA-G. This could facilitate the polymerization leading to higher molar mass. Furthermore, the 7.5:1 mixture of the p,p'/m,p'-regioisomers in 3 may contribute to the higher Ð and more supple nature of the resulting polymer. The higher flexibility of the 3-G monomer compared to BPA-G was further illustrated by the corresponding properties of the 3-G-DMS and BPA-G-DMS polymers (Figure ). Dynamic mechanical analysis (DMA), using films with dimensions of 30 mm × 5 mm × 0.5 mm (length × width × thickness), demonstrated that the storage modulus (E′) of the glassy plateau was observed at 24 °C for the 3-G-DMS polyester and at 34 °C for its BPA analogue. These observations correlate well with glass transition temperatures (Tg) of 22 °C and 33 °C for 3-G-DMS and BPA-G-DMS, respectively, as determined from the temperatures at which the of E″ reached local maxima (tan δ max). This trend was further verified when assessing the Tg values by differential scanning calorimetry (DSC) (Figure , Table ). While polymer materials are typically rigid and glassy-like below Tg, an elastic and rubbery behavior is observed when the temperature is above Tg. Similarly, a lower Tg reflects a more flexible chain structure that can retain the ability to rotate even at lower temperatures. As such, the lower Tg of the 3-G-DMS polymer suggested that this material was more supple compared to the more rigid BPA analogue. In agreement, the mechanical properties of the two polyesters determined by tensile testing at room temperature, demonstrated that BPA-G-DMS exhibits higher elastic modulus and lower elongation at break, i.e., it is stiffer and less flexible compared to 3-G-DMS (478.2 vs. 185.1 MPa and 65% vs. 237%, respectively). Interestingly, both polyesters displayed very good thermal stability, as evaluated by thermogravimetric analysis (TGA), with thermal degradation onsets (T5) at ~345-370 °C and degradation maxima (Td) at ~390-400 °C. As expected, both polyesters were thermally more stable (~60 °C higher T5 values) compared to the corresponding glycolated bisphenol monomers as a result of their higher molar masses and decreased content of end groups after polymerization. The char yields (CY) of both polymers after TGA pyrolysis at 600 °C were determined to be 26-28%, which is typical for polymer with high content of aromatic structures. Finally, the DSC analysis confirmed that both polyesters were completely amorphous.