With nanostructured materials the light-matter interaction can be strongly influenced resulting in a broad application potential in optics and optoelectronics. With nanostructured materials the degree of freedom of electrons and the propagation of light in matter can be controlled and restricted down to a full localization of electrons and photons. With that one can obtain a drastic enhancement of the light-matter interaction not achievable in macroscopic materials. For that purpose semiconductor, dielectric materials and metals are used to realize, e.g., electronic quantum dots, optical microcavities or plasmonic effects in metallic nanostructures. These approaches open new possibilities for a new generation of highly efficient optical and optoelectronic devices as well as for a new area of optically based quantum information technology, in which the information is only stored in single particle properties like electrons, photons or coupled quantum systems.