Not a molecule, not a polymer, not a substrate ... the many faces of graphene as a chemical platform

What is, exactly, graphene? While we often describe graphene with many superlative adjectives, it is difficult to force this material into a single chemical class. Graphene's typical size is atomistic in one dimension of space, and mesoscopic in the other two. This provides graphene with several, somehow contrasting properties. Graphene can be patterned, etched and coated as a substrate. Though, it can also be processed in solution and chemically functionalized as a molecule. It could be considered as a polymer, obtained by bottom-up assembly of carbon atoms or small molecules, but it can be obtained also from top-down exfoliation of graphite (a mineral). It does not have a well-defined shape, such as that of fullerenes or nanotubes; conversely, it is a large, highly anisotropic, very flexible object, which can have different shapes and be folded, rolled or bent to a high extent. In this feature article, we will discuss the state of the art and possible applications of graphene in its broader sense with a particular focus on how its "chemical" properties, rather than its well-known electrical ones, can be exploited to develop original science, innovative materials and new technological applications.