A process for preparing substituted biphenyls of the formula I where R1=nitro or amino, R2=cyano, halogen, C1-C4-haloalkyl, C1-C4-haloalkoxy or C1-C4-haloalkylthio, n=from 0 to 3, and R3=hydrogen, cyano or halogen, which comprises reacting a halobenzene of the formula II in which Hal is chlorine or bromine, in the presence of a base and of a palladium catalyst which consists of palladium and a bidentate phosphorus ligand of the formula III where Ar is phenyl which is substituted if desired and R4 and R5 are each C1-C8-alkyl or C3-C6-cycloalkyl or together form a 2- to 7-membered bridge which may, if desired, bear a C1-C6-alkyl substituent, in a solvent or diluent, with a phenylboronic acid IVa a diphenylborinic acid IVb or a mixture of IVa and IVb.