The active sites found on the surfaces of heterogeneous catalysts, in enzymes and in solution chemistry bear more resemblance with regard to structure and reactivity than usually assumed. This is illustrated in this perspective article with a few precedent cases showing how the different areas may benefit from each other, when treated together. Findings concerning the methane-oxidizing sites inherent to oxygenated Cu-ZSM-5 are discussed with a view on the active site of the pMMO and models thereof. Polydentate siloxide ligands were found suitable to simulate the ligation of transition metal ions by zeolite frameworks or silica surfaces, so that corresponding iron complexes turned out to be valuable spectroscopic models for the active sites of iron-modified zeolites. Polynuclear copper siloxides proved advantageous precursors for the generation of novel heterogeneous oxidation catalysts. Combining the findings that chromium sites on silica supports possess unique properties and that chromium(II) complexes in solution exhibit interesting reactivities towards dioxygen led to the development of chromium(II) siloxide compounds with unique features for O-2 activation. [GRAPHICS] .