Abstract: Chemical reactions are mainly studied in solutions. Most of the natural and biological reactions take place, however, in organized assemblies, e.g. membranes, vesicles, micelles, and in supramolecular structures, in viscous soft or even solid environments. Reactive molecules in organized assemblies and in solid phases behave differently than in solutions. The influence and importance of external factors such as solvent, temperature, distances, and anisotropy are changed. An important question remains, whether the reactions still could be described as a thermally activated process as suggested by the classical theories. Several techniques provide precise control over the film thickness and a possibility to construct multilayer structures with desired layer sequences on large areas. When external light is used for creating reactions, i.e. working with photochemistry, a new aspect, ultra-fast processes, will play an important role. The interaction of photons with films with thicknesses of a few nanometers is a potential component in different applications and devices such as displays, sensors, electronic circuits, and photovoltaics.
