We perform bioinorganic chemistry within organic cages. We have a great passion for the development of endo- and exo-functionalized cage-compounds. We aim to mimic the ligand sphere of active sites of prominent enzymes. Such bio-inspired transition metal-complexes are investigated for their abilities to activate and transform small molecules or to catalyse organic transformations. We further use these cage-complexes to perform spectroscopic studies on them and to compare the results with data obtained from enzymes. We hope to learn in this manner more about enzymatic active sites.