A simple and efficient procedure for the synthesis of 5-substituted-1H-tetrazoles via the [3+2] cycloaddition reaction of nitriles with sodium azide was developed. The reaction occurred in DMF at 120°C in the presence of a reusable and an environmentally friendly ZnFe2O4@SiO2–SO3H heterogeneous magnetic nanocatalyst prepared in the present work. The new catalytic system was characterized by FTIR spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) spectroscopy, and vibrating sample magnetometry (VSM). The results showed that the ZnFe2O3@SiO2–SO3H nanoparticles are highly efficient for this organic reaction. The methodology offers such benefits as quick reaction, high yields of the desired product, clean process, as well as the low-cost heterogeneous catalyst and its low loading, simple separation, and recyclability. [ABSTRACT FROM AUTHOR]