Atomically defined nanoclusters composed of a few atom metal core (dimension ˂3 nm) protected by surface ligands have various atom-specific functional properties. The structure-property correlation of such materials depends on their structural resolution through X-ray and neutron diffraction techniques. Although mass spectrometric studies reveal molecular composition in the solution and gas phase, solid-state techniques lagged behind due to the difficulty of their crystallization. Different methods have been adapted to grow suitable quality crystals used for diffraction studies. A highly ordered assembly of nanoclusters in a single crystal is essential for understanding the atomic structure. The partially ordered assembly resulted in gel fibrous and disordered assembly of clusters makes confined solids. This chapter presents the growth of crystals, gels, and confined solids of various gold, silver, and copper nanoclusters. We have also discussed different solid-state properties and associated applications of such nanomaterials. © 2023 Elsevier Inc. All rights reserved.