In this study, new indenopyrimidin-1,2,4-triazol derivatives were synthesized in high yields using multicomponent reactions of ninhydrins, guanidine, alkyl bromides, aldehydes and hydrazonoyl chloride in the presence of Fe3O4/CuO/ZnO@Multi-Walled Carbon Nanotube Magnetic Nanocomposites (Fe3O4/CuO/ZnO@MWCNT MNCs) as a high performance catalyst in water at room temperature. The Fe3O4/CuO/ZnO@MWCNT MNCs was prepared using Petasites hybridus rhizome water extract as a green media and moderate base. This procedure had some benefits such as short reaction time, products with excellent yields, simple catalyst and products separation. The Fe3O4/CuO/ZnO@MWCNT MNCs was showed a good improvement in the yield of the product and displayed significant reusable activity as well. Investigation of antioxidant ability of synthesized compounds using radical trapping of diphenyl-picrylhydrazine (DPPH) and ferric reduction power experiment were another purpose in this research. Green chemistry is the use of a set of principles to reduce or eliminate the use or generation of unsafe materials in the design, fabrication and applications of chemical products. Among solvents, water is a green solvents and very suitable for performing organic reaction. The present procedure avoids the use of toxic solvent. Substituted 1,2,4-triazoles and their derivatives are key skeleton of many biologically active molecules and important organic compounds that exhibit wide applications in pesticides, medicines, functional materials and organocatalysts. [ABSTRACT FROM AUTHOR]