Abstract Applying DFT methods, the reductive elimination reaction of bis(pyridyl) rare-earth metal cation [Ln( η 2 -C,N-pyridyl) 2 (THF) 3 ] + (Ln = Y, La) was studied. The effect of both electron-donating and electron-withdrawing substituents in the para -position of the pyridine ring was considered. An alternative mechanism for the C–C coupling reaction between pyridine derivatives (pyridine, DMAP and 4-trifluoromethyl-pyridine) and [LnMe 2 (THF) 5 ] + (Ln = Y or La) is suggested. The reaction involves a single electron reductive C–C coupling to form of Ln(II) complexes with a bipyridine radical anion.