Obtaining structurally uniform nanocarbons in order to properly relate structure and function, ideally as single molecules, is a great challenge in the field of nanocarbon science. Thus, the construction of structurally uniform nanocarbons is crucial for the development of functional materials in nanotechnology, electronics, optics, and biomedical applications. An important tool for achieving this goal is molecular nanocarbon science, which is a bottom-up approach toward creating nanocarbons using synthetic organic chemistry. However, the molecular nanocarbons synthesized so far have simple structures, such as that of a ring, bowl, or belt. In order to realize unexplored and theoretically predicted nanocarbons, it is necessary to develop new methodologies for synthesizing molecular nanocarbons with more complex structures.