Compared with inorganic two-dimensional (2D) materials, such as graphene and transition metal dichalcogenides, organic 2D materials are believed to possess more interesting chemical and biological properties for certain applications, such as separation membranes, smart surfaces, sensors, catalysis and drug delivery. However, the study of organic 2D materials is largely hindered because of the lack of effective methods to produce them. This paper presents a new type of organic 2D material, namely ‘polymer@graphene 2D objects’, that can be synthesized via a simple and scalable chemistry. Polymer@graphene 2D objects are made of functional polymer brushes that tether one end of the polymer chain on the surface of graphene sheets via non-covalent π-π stacking interactions. These materials are transparent, freestanding, lightweight, flexible, transferable to various substrates with good stability and are patternable into different structures. Their functionality can be tailored by changing the polymer brushes that are immobilized. In this paper, we demonstrate the applications of these 2D objects in the smart control of surface wettability and DNA biosensors.