This research project uses a combination of theory, numerical simulation, and experiment to discover and synthesize new crystalline materials that can enable the manufacturing of metamaterials. Metamaterials have unique periodic structures that can be used to manipulate electromagnetic or mechanical energy. The materials are formed from the self-assembly of colloidal particles in suspension. This route to metamaterials is especially flexible, because many kinds of interactions among the particles can be exploited to form new crystalline materials. In addition, it allows better control over the formation process, which can reduce defects in the resulting crystalline structures. Three specific platforms to be considered are solid-fluid and solid-solid polymorphic transitions in binary mixtures of spherical particles of different size and interaction potential, plastic to close-packed solid transitions for doublet/dumbbell particles, and the formation of non-close-packed structures for particles with orientation-dependent attraction (Janus). The results of the project will provide scientists and engineers with improved tools for identifying colloidal systems of interest, predicting stable crystalline structures, and guiding synthesis of the new materials.