ABSTRACT Sustainable hydrogen generation through water splitting is key to realizing a future hydrogen economy. In this study, we achieved molecular‐level control over self‐assembled supramolecular complexes of cyanuric acid and 3‐amino 1,2,4 triazole (AT) monomers. This was coupled with molten‐salt‐assisted thermal polymerization in a eutectic mixture of lithium chloride and potassium chloride to synthesize a crystalline carbon nitride with a high surface area and specific crystal structure. Co