In the last years, experimental research in the field of chemistry and materials science is increasingly focusing on molecular systems self-assembled on the nanometer scale. The interest in ordered structures came from the study of biological systems, which are built up by simple molecules arranged into complex structures, which create a wide range of diverse functions. The cell is an example of features integrated into an intricate whole. We are not yet able to reproduce the complexity of a biological system like the cell, but we learned that the assembly of single molecules as components of a more complex system is the key issue to reaching new functional materials.