A highly luminescent LnMOF {[Eu2(bqdc)3(H 2O)(DMF)3]·0.5DMF·H2O} n (1, bqdc = 2,2′-biquinoline-4,4′-dicarboxylate) was designed and synthesized. It was characterized by single crystal X-ray diffraction, PXRD, TGA, EA and FT-IR. A new strategy for preparing mechanically robust MOF thin films was developed by electrodeposition in combination with subsequent solvothermal synthesis. A portable sensor device prototype consisting of a film of 1 was conveniently fabricated by using this new strategy and this sensor device exhibits a highly selective response to Hg2+. Its luminescence quenching can be distinguished clearly with the naked eye when illuminated by a handy UV banknote detector. The diffusion kinetics of Hg 2+ into the LnMOF film is first proposed. ; Department of Applied Biology and Chemical Technology