Although optical coating deposition techniques have been perfected over decades to prepare optically homogeneous dense coatings with smallest surface roughness, nanostructuring of optical coatings has proven as an effective mechanism to further enhance their performance while reducing their thickness in special cases. Therefore, nanostructure effects can be tackled as additional degrees of freedom for coating design, and can even lead to useful property combinations that are inaccessible to ' classical ' coatings prepared on the basis of the traditionally available coating materials. Examples include metal island fi lms as building blocks for spectrally selective absorber coatings for color management or solar energy conversion purposes, as well as motheye structures for antirefl ection coatings and the combined optimization of optical and non-optical coating properties.