Metal-Organic Frameworks are crystalline coordination polymers, which represent a new, interesting class of porous solids. They are fairly stable, exhibit well-defined mechanical properties, and can be prepaired in a highly reproducible fashion on solid substrates. We demonstrate here that this crystallline, highly ordered porous coatings are well suited as model systems to study molecular interactions in porous media in a quantitative fashion, including diffusion and optical switching between different molecular states. In addition, they are also qualified to study electrical transport through molecular frameworks and transfer of optical excitations. Because of their crystalline nature, they are well-suited for quantitative comparisons with results from theoretical work.