4,4'-Dimethylbiphenyl is used in the preparation of biphenyl-4,4-dicarboxylic acid, which acts as a monomer utilized in the synthesis of linear long chain polymer through polycondensation reaction. It is used to prepare 4-(4'-methylphenyl)benzaldehyde by selective photoxygenation reaction using 9-phenyl-10-methylacridinium perchlorate as a catalyst under visible light irradiation.
Guo, M.; Qi, L.; Lv, M.; Zhou, X.; Liang, H.; Chen, S. Homocoupling of Arylboronic Acids Catalyzed by a Simple Hydrophilic Palladium(II) Complex in Aqueous Media. Lett. Org. Chem. 2015, 12 (3), 205-209.
Raul, P. K.; Mahanta, A.; Bora, U.; Thakur, A. J.; Veer, V. In water homocoupling of arylboronic acids using nano-rod shaped and reusable copper oxide(II) catalyst at room temperature. Tetrahedron Lett. 2015, 56 (51), 7069-7073.