(NHC) 2FeCl2 complexes undergo methoxide transfer in preference to aryl transfer from [(Aryl) B (OR) 3]−, while addition of ArylBY2 (Y= Cl, OR) to (NHC) Fe–methoxide compounds leads only to formation of (NHC) BY2Aryl. The addition of PhBCl2 to (NHC) 2FeX2 compounds is introduced as a method for probing NHC dissociation from iron. Two expanded ring NHCs also undergo dissociation from iron in the respective (NHC) 2FeCl2 ...