In this research 2-aminoethanesulfonicacidimmobilized on epichlorohydrin functionalized Fe3O4@WO3 (Fe3O4@WO3-EAE-SO3H) has beenintroduced as a novel and efficient magnetic nanocatalystfor appropriate and rapid synthesisof 1-substituted-1H-1,2,3,4-tetrazoles. This new nanocatalyst was then characterized using FT-IR, XRD, TEM, EDS, TGA, FE-SEM, CHNS and VSM techniques. The above experimental results allowed determination of the composition of Fe3O4@WO3-EAE-SO3H and clearly revealed that the nanoparticles are sphericalin shape with particlesizein the range of 7­23 nm and superparamagnetic behavior. Fe3O4@WO3-EAE-SO3H as an excellent replacement for Brønsted acids was shown to be highlyefficientin the rapid preparation of1-substituted-1H-1,2,3,4-tetrazoles through the cyclization reaction of various primary amines, triethyl orthoformate and 1-butyl-3-methylimidazolium azide ([bmim][N3]). Compared with conventional methods, the present protocol has considerable advantages such as short reaction time, mild reaction conditions, easy work-up, pure products with high yields, catalyst recovery using an external magnet and reuse of the catalyst several times without noticeable deteriorationin catalytic activity. In addition to the aforementionedfavourable properties, the remarkablefeature ofthe present protocolis the use of water as environmentally benign solvent, which eliminates the use oftoxicsolvent

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