 Intermolecular FLPs are where the Lewis Base is a separate molecule to the Lewis Acid, it is thought that these individual molecules interact through secondary London dispersion interactions to bring the Lewis Base and Acid together (a pre-organisational effect) where small molecules may then interact with the FLPs.The experimental evidence for this type of interaction at the molecular level is unclear.However, there is supporting evidence for this type of interaction based on computational DFT (Density Functional Theory) studies.