This chapter describes an approach toward the rational development of functional nanomaterials (or nanodevices). It focuses on a “study case” that represents a good example. The example comprises methodologies and experimental pros and cons that can be applied to other projects. Generally speaking, people can identify four distinct stages involved in the development of a nanodevice, but they are all strongly interconnected: the output of one stage is used as input for the next one. They are formulation/refining of a starting idea or hypothesis, which requires devising a specific system, fabrication of the different components and their assembly into the desired structure, systematic and detailed characterization of the produced materials, and interpretation of the experimental data on the basis of existing or new theory. These four stages can be organized in a cycle, where each “round” represents a step forward toward the design of a new functional material.