Treatment of (Tp tBu,Me )YbE(thf) (E=I (1), CH 2 SiMe 3 (2)) with tetramethylimidazol-2-ylidene (ImMe 4 ) resulted in very different outcomes depending on the nature of the anionic ligand E. ImMe 4 acts as a simple Lewis base toward 1 resulting in substitution of the thf (tetrahydrofuran) ligand and formation of (Tp tBu,Me )YbI(ImMe 4 ) (3). However, reaction with 2, in addition to displacement of thf, proceeded by metalation of one of the N–CH 3 substituents of ImMe 4 and gave (Tp tBu,Me )Yb(ImMe 4 )(CH 2 N(C(CH 3 )C(CH 3 )N(CH 3 )C) (4), featuring a hydrocarbyl tethered carbene ligand. The X-ray structures of 3 and 4 are reported.