A method of preparing graphdiyne-based material and a substrate for use in such material preparation process. The method includes the steps of: disposing an alkynye-based monomer on a substrate; maintaining a planar structure of each of a plurality of molecules of the monomer on a surface of the substrate; and initiating polymerization of the monomer on the substrate to synthesize a two-dimensional crystalline layer of the graphdiyne-based material on the substrate.