What could be cooler than a technology that uses nanomaterials? How about one with two nanomaterials working together? Nanocomposites bring together two or more nanoscale materials to take advantage of their combined features to get what Dr. Klaus Müllen calls "the best out of two worlds." Dr. Müllen is an emeritus director at the Max Planck Institute for Polymer Research, where his work ranges from the chemistry and physics of small molecules to nanocomposites and biosynthetic hybrids. In this interview he talks about how a fascination with color got him into chemistry, some of the many technological applications for nanocomposites, and some candid advice for young scientists.