Abstract Arylation of ferrocene with substituted biphenyldiazonium tetrafluoroborates afforded 4-bromo-, 4-nitro-, and 4-cyano-4"-ferrocenylbiphenyls. 4-Nitro-and 4-cyano-4"- ferrocenylbiphenyls were studied by X-ray diffraction analysis. In the crystals of 4-nitro-4"- ferrocenylbiphenyl, the molecules are linked via stacking π-π interactions.