<p>Benzimidazoles are a class of heterocyclic compounds traditionally known for their antiparasitic and antitubercular properties. Herein, an amine-functionalized NH₂-MIL-88B(Fe)/Ag₂WO₄ (abbreviated as MIL/Ag₂WO₄) photocatalyst applied as an effective mediator in the one pot preparation of some selected heterocyclic 2-substituted benzimidazole derivatives under illuminating a commercial HP-Hg, 200W. Comprehensive characterizations including FT-IR, EIS, PXRD, FE-SEM, EDS, TGA, and UV-DRS are used to elucidate structural and functional properties of the photocatalyst. Electrochemical impedance spectroscopy (EIS) studies confirmed that the prepared heterojunction provides a higher charge-mobility and acceptable photocatalytic activity. The Mott-Schottky (M-S) plots suggested that the MIL counterpart is an n-type semiconductor, while Ag₂WO₄ would be a p-type semiconductor, therefore, MIL/Ag₂WO₄ would be a Z-scheme p-n heterojunction photocatalyst, enhancing the redox ability, increased charge mobility, and allowing formation of photocatalytic-active species. The key advantage of MIL/Ag₂WO₄ photocatalyst is its remarkable stability, demonstrated by its consistent performance over seven cycles with little loss of catalytic utility. High reusability of MIL/Ag₂WO₄ reduces waste and costs, while its mild operational conditions minimize using toxic chemicals, contributing to environmental benign synthesis conditions.</p>