The many-body optical response of disordered plasmonic nanoparticle assemblies can be continuously tuned through their colloidal building blocks' structural organization and composition. However, progress in the design and experimental realization of these materials has been limited by challenges associated with controlling and characterizing disordered assemblies and predicting their optical properties. In this talk, I’ll discuss experimental studies of the assembly of disordered optical materials, such as doped metal oxide nanocrystal gel networks, informed by electromagnetic computations on large-scale simulated structures. The simulations illustrate how disordered structure modulates optical properties, and how optical measurements can help characterize nanoscale structure.