A range of cationic rhodium bisphosphine η6-fluorobenzene (fluorobenzenes = C6H6−nFn, n = 1–3) and related complexes have been synthesized and characterized. These complexes act as useful organometallic precursors for catalysis or further synthetic elaboration. The relative binding affinity of the arene ligands has been investigated using Electrospray Ionisation Mass Spectrometry (ESI–MS) and two different collision-induced dissociation (CID) techniques. The influence of arene fluorination upon arene binding affinity is discussed as well as the comparison of different bis–phosphine ligands with regard to bite angle and phosphine substitution. We show that this simple technique allows fast and easy comparison of the binding affinity of arene ligands to cationic organometallic fragments.