Using tetraaryllead compounds (PbAr4) asarylating reagents, isocyanides undergo selective diarylationin the presence of palladium catalysts such as Pd(OAc)2 orPd(PPh3)4 to afford imines and/or α-diimines based on theisocyanide employed. With aliphatic isocyanides, imines areobtained preferentially, whereas α-diimines are formed in thecase of electron-rich aromatic isocyanides. The differences inimine/α-diimine selectivity can be attributed to the stability ofimidoylpalladium intermediates formed in this catalytic reaction. Compared with other arylating reagents, tetraarylleadcompounds are excellent candidates for use in the selective transformations to imines and/or α-diimines, especially in terms ofinhibiting the oligomerization of isocyanides, which results in a lower product selectivity in many transition-metal-catalyzedreactions of isocyanides.