An iridium center transfers a methyl group from pyridinium to an aryl unit, using exclusively the pyridine-bound methyl group as a mild methylene source. The reaction also involves cleavage of an unactivated C(aryl)[BOND]H bond and nitrile solvent activation. The process is reminiscent of DNA methylation and entails the formation of two new C(sp2)[BOND]C(sp3) bonds within the metal coordination sphere (see scheme).