Beginning with the humble pencil, graphene has evolved to play a vital role in nanomedicine, particularly in the early detection of abnormalities and effective treatments thereof. Graphene and its derivatives have recently attracted much interest in various fields, including biomedicine, due to their exceptional physical and electrochemical properties. Owing to the high customizability, tuneability, and potential to functionalize using multiple biomolecules, the prospect of graphene to realize theranostic applications holds great promise for the advancement of modern healthcare. Theranostic applications like biosensing, drug delivery, “hybrid theranostics”, etc., benefit significantly from the said functionalization. This is because they enhance graphene's solubility, stability, and loading capacity, among other properties. Recent applications also include multi-modal imaging and imaging-guided therapy, particularly in the case of Cancer. In this chapter, various aspects of 3D graphene-based theranostic modules, including fabrication and functionalization techniques, have been discussed, along with multiple applications and advantages. The recent advancements and challenges faced therein have also been elaborated upon. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.