"Many materials in the form of well-defined nanoscale crystals (“nanocrystals”) exhibit unique properties due to size effects and large surface-to-volume ratios. Yet it is clear that the utilization of nanomaterials in modern technologies requires their integration into solid-state structures with programmable electronic, magnetic and optical properties. The clear challenge is the rational design of this novel type of condensed matter, in which the size-tunable individual properties of nanoscale building blocks are enhanced by their interactions and by the macroscopic properties of their ensembles. The project NANOSOLID will rethink existing approaches and propose radically new strategies for the bottom-up assembly of inorganic entities of various dimensionalities into functional inorganic materials. We identified two clear and interlinked needs that will be addressed: the proper design and understanding of nanocrystal surface chemistry, and the unconventional assembly of nanocrystals into dense nanostructured solids. The union of modern concepts from molecular and supramolecular chemistry will be used to develop nanosolids with predictable geometries and functionalities. We will combine colloidal nanocrystals with other well-established classes of materials aiming at previously unknown crystalline structures composed of strongly interacting species in search for ground-breaking advances in materials design. Among the possibilities for these investigations are covalent and non-covalent, directional and non-directional binding modes, and specific and non-specific interparticle interactions. Together, this project will contribute significantly to the fundamental knowledge about the nanocrystal surface, and will develop new synthetic design tools for complex inorganic solids. Overall, the new materials design platform is expected to bring the long-awaited innovative solutions in energy research, particularly in the areas of thin-film devices for energy conversion and storage."