Chapter 1: This consists of a literature review and an introduction into the variety of computational techniques and methodologies available. Chapter 2: The molecular modelling of alkali metal complexes with calixarenes. We have published three papers in this area1. The HyperChem molecular modelling software package has been demonstrated to be a straightforward and computationally undemanding technique that is surprisingly good at reproducing the structures of a range of metallocalixarenes. Chapter 3: The molecular modelling of the enantioselective complexation of chiral amines by chiral calix[4]arenes. With reference to the enantioselective complexation studies we have shown that by using molecular modelling software, an insight can be gained into the interactions that occur on complexation of chiral amines by chiral calixarenes. By observing the hydrogen bonding patterns formed between the host and guest we can postulate why one enantiomer interacts more strongly than the other and, hence, provide a plausible explanation for the observed enantiomeric selectivity observed in the fluorescence quenching experiments. Chapter 4: The catalysis of the Diels Alder reaction by ionic liquids. The first example of the usage of dialkylimidazolium salts (R2 lm+X‘) as heterogeneous and homogeneous Lewis acids catalysts in the Diels-Alder reaction is detailed in a published paper .