A novel magnetic nanocomposite, MnFe₂O₄/Cu, was synthesized by coating manganese ferrite nanoparticles prepared via a solid-state method using hydrated Fe (III) nitrate and Mn (II) salts in the presence of NaOH and NaCl with copper nanoparticles, followed by calcination at high temperatures. The resulting nanocatalyst was applied in a one-pot, three-component click reaction in aqueous medium. Various epoxides bearing electron-donating and electron-withdrawing substituents reacted with thiourea under solid-phase conditions to produce the corresponding thiiranes. Subsequently, thiiranes with alkyl, allyl, and aryl groups underwent ring-opening and cycloaddition with phenylacetylene and sodium azide in the presence of MnFe₂O₄/Cu in water under reflux conditions to afford β-thiol-1,2,3-triazole derivatives. The reaction progress was monitored by thin-layer chromatography (TLC), and the effects of temperature, solvent, and catalyst amount were systematically studied. Optimal conditions were identified as 0.03 g of catalyst at 100 °C in water, and the catalyst was successfully reused for four consecutive cycles. The structure of the nanocomposite was characterized by EDS, FT-IR, SEM, and VSM, and the structures of the triazoles were confirmed by melting point, ¹³C NMR, and ¹H NMR analyses. This study demonstrates an efficient, green, and recyclable approach for the synthesis of β-thiol-1,2,3-triazoles from thiiranes under aqueous conditions.