From an experimental study on H-ZSM-5 zeolite, it is shown that an optimal proportion of Brønsted Strong Lewis Pairs (BSLP) are responsible for the observed amount of adsorbed trans-Stilbene radical cations. A mechanism for their formation and the charge transfer complex (CTC) is also proposed.

From experimental results on H-ZSM-5 and H-*BEA zeolites, it is shown that the stability of radical cations and of charge transfer complexes (CTC) is highly dependent on the distance between Brønsted sites and strong Lewis sites or Brønsted Strong Lewis Pairs (BSLPs).