In this study, ZnO/Ag/Fe 3 O 4 /CNTs nanoparticles (NPs) immobilized on carbon nanotubes (ZnO/Ag/Fe 3 O 4 /CNTs) were synthesized using Petasites hybridus rhizome water extract as a renewable, mild, and safe reducing agent and effective stabilizer without adding any surfactants. For the confirmation of the structure of the green synthesized NPs, various methods such as X-ray diffraction (XRD), FESEM, transmission electron microscopy (TEM), Energy-Dispersive X-Ray Spectroscopy (EDS), and Vibrating Sample Magnetometer (VSM) were employed. The ZnO/Ag/Fe 3 O 4 /CNTs magnetic NPs as a high performance catalyst was employed for the preparation of naphthyridine derivatives in high yields via the multicomponent reactions of phthalaldehyde, 2-aminoactonitrile, activated acetylenic compounds, α-haloketones, triphenyphophine, and ammonium acetate in aqueous media at ambient temperature. Due to having isoquinoline core, we investigate antioxidant property of some synthesized compounds by diphenylpicrylhydrazine (DPPH) radical trapping and power of ferric reduction experiment. Furthermore, the disk diffusion test on Gram-positive and Gram-negative bacteria IS utilized for investigation of antimicrobial activity of some naphthyridines. The achieved outcomes of this experiment demonstrate that these synthesized compounds could prevent from growth of bacteria. Short time of reaction, high yields of product, easy separation of catalyst, and products are some benefits of this process. K E Y W O R D S alkyl bromide, multicomponent reaction, naphthyridine derivatives, ZnO/Ag/Fe 3 O 4 /CNTs nanoparticles 1 | INTRODUCTION The naphthyridine derivatives are significant heterocyclic compounds due to their broad spectrum of biological activities such as antihypertensives, antiarrhythmics, herbicide safeners, and immunostimulants. [1-3] The compounds containing a naphthyridine scaffold are a small class of bispyridine structures identified in various living organisms (plants, sponges, tunicates, and bryozoans). These natural products usually possess variant biological