The computational prediction of IR spectra clearly showed that different bonding environments of 5-FU could be easily distinguished by means of IR spectroscopy. Although significant discrepancies between the DFT results and previously reported experimental data were apparent, these are most probably attributable to the interaction of 5-FU with EFAL sites in the experimentally studied samples. Future computational work will look into a DFT-based modelling of the interaction between 5-FU and EFAL sites, taking EFAL models proposed in the recent literature as starting points. While it might appear counterintuitive that all three samples studied experimentally in prior work show identical shifts of IR-active modes, it has to be considered that even the most Si-rich sample contained, on average, 6 Al atoms per unit cell (Si/Al ratio of 30). Thus, it still seems possible that a significant fraction of the adsorbed 5-FU molecules can interact with EFAL sites. However, these aspects cannot be elucidated with calculations alone, and a more detailed understanding of the role of different aluminium environments would require further experimental investigations of 5-FU adsorption in zeolite samples having well-quantified amounts of framework and extra-framework Al atoms.