Co3O4 / NiO @ GQDs @ SO3H nanocatalyst has been used as an effective catalyst for the preparation of 2,4-diamino-6-arylpyrimidine-5-carbonitrile derivatives through a three-component reaction of malononitrile, aromatic aldehydes and guanidine hydrochloride under reflux conditions in ethanol. The catalyst has been characterized by FT-IR, XRD, SEM, EDS, BET, TGA, XPS and VSM. Atom economy, reusable catalyst, low catalyst loading, applicability to a wide range of substrates and high yields of products are some of the notable features of this protocol.The best results were gained in EtOH and we found that the reaction gave convincing results in the presence of Co3O4/NiO@GQDs@SO3H nanocomposite (4 mg) under reflux conditions. This green nanocatalyst could be used for other significant organic reactions and transformations. Further explorations of similar protocols are underway in our laboratory. This recoverable catalyst will provide a regular platform for heterogeneous catalysis, green chemistry, and environmentally benign protocols in the near future. Manuscript profile