4,4'-Dicarboxydiphenyl Ether (DCPE) is a polymer raw material that can undergo polycondensation with terephthalic acid (TA) to produce poly(aryl ether benzimidazole) copolymers for use in high-temperature fuel cell membranes.
White to pale brown solid
4,4'-oxybisbenzoic acid is a monomeric liquid crystal polymer. it is used widely in the electronics and pharmaceutical industries. Preparation of whole Polyarylate thermoplastic liquid crystal polymer (TLCP), also can be used to prepare high strength, high modulus of liquid crystal fibers, specialty plastics and polymer flame retardants in industrial. also as a non-liquid crystal polymer additives, reduce baking temperature and viscosity of the polymer to facilitate processing and made of an insulating material.
Based on Friedel–Crafts acylation, nonstoichiometric polycondensation was achieved using 4,4'-Dicarboxydiphenyl Ether and 2,2′-dimethoxybiphenyl in trifluoromethanesulfonic acid
[1].

4,4'-Oxybisbenzoic acid can be prepared by reacting 4-chlorobenzoic acid and 4-hydroxybenzoic acid under certain conditions.
[1] Matsumoto, K., Ogawa, T., Jikei, M. (2017). Nonstoichiometric polycondensation based on Friedel–Crafts acylation in superacids for the syntheses of aromatic polyketones†. Polymer Chemistry, 47, 7297–7300. https://doi.org/
10.1039/C7PY01609C