▎ 摘　　要

van der Waals (vdW) heterostructures generated by stacking of graphene with other two-dimensional (2D) crystalline sheets have produced a new class of "designer" materials which shows great promise for nanoscience and nanotechnology. However, the 2D sheets are obtained either from nature or synthesized by high-energy procedures, which preclude the design of their structures as well as properties from molecular design on demand. Here, we introduced a rationally designed 2D polymer (one-monomer unit thick, freestanding network composed of periodically linked monomers) as a component for heterostructure construction, and created a 2D polymer-graphene heterostructure. The heterostructure has a high chemical stability, and could be thermally stable up to 400 degrees C. In the heterostructure, the 2D polymer doped graphene without changing its intrinsic structure, leading to the enhancement of its electric conductivity by a factor of similar to 2.5. This piece of work opens the door to tune the properties of graphene heterostructures with rational design for specific applications.