Cover Picture (Angew. Chem. Int. Ed. Engl. 2/1995)

The cover picture shows the structure, generated by molecular mechanics calculations, of a chromophoric self-assembled superlattice with a very large second-order nonlinear optical response (blue, benzylic coupling layer; green: stilbazolium chromophore layer with high polarizability: violet and yellow: siloxane capping layer: white spheres: iodide counterions). The synthesis and properties of the associated real systems are one of the themes of the review by T. J. Marks and M. A. Ratner on molecule-based assemblies with nonlinear optical properties on pp. 155ff. This article complements excellently that by N. J. Long on the “organometallic route” to NLO materials in the previous issue.