The unique properties of plasmonic nanostructures have fuelled research based on the tremendous amount of potential applications. Their tailor-made assemblies in combination with the tunable size and morphology of the initial building blocks allow for the creation of materials with a desired optical response. In this respect, it is crucial to synthesize nanoparticles with a defined shape that are at the core of such developments. Moreover, the interaction of individual nanoparticles with an incident electromagnetic field cannot only be influenced by their structure, but in fact, also by their spatial arrangement to each other. To harvest such opportunities, a profound theoretical understanding of these interactions is required as well as concise strategies to create such ordered assemblies. A quantitative evaluation of their optical properties can only be conducted when discrete structures of high uniformity can be achieved. As a consequence, separation steps have to be applied in order to obtain materials of high purity and uniformity. This also allows for an easier structural characterization of the nanoparticles and their assembled superstructures. In this progress report, an overview about the current development in this field of research is provided.