<p> Four lanthanide metal-organic frameworks (Ln-MOFs) with the same planar structure were successfully synthesized via the hydrothermal method：{DyL (H₂O)₃·5H₂O}ₙ (<b>1</b>), {HoL(H₂O)₃·5H₂O}ₙ (<b>2</b>),{ErL(H₂O)₃·5H₂O}ₙ (<b>3</b>), and {TmL (H₂O)₃·6H₂O}ₙ (<b>4</b>), where H₃L = 2,4,6-biphenyl tricarboxylic acid. All four Ln-MOFs crystallize in the triclinic P_-1 space group, exhibiting high phase purity, excellent thermal stability, and favorable luminescence properties. The Ln-MOFs powders were subsequently shaped into composite fluorescent films using a polymer embedding method for the sensing and detection of Fe³⁺, Cr₂O₇²⁻, aspartic acid (Asp), and tetracycline (Tcn) in aqueous solutions. It was found that&#xa0;<b>1</b>@PMMA,&#xa0;<b>2</b>@PMMA, and <b>4</b>@PMMA exhibited significant recognition ability for Asp, with no notable differences among them.&#xa0;All three films could serve as fluorescence sensing probes for Asp. In contrast, <b>3</b>@PMMA showed no distinct recognition ability for Asp. For the detection of Tcn, Fe³⁺, and Cr₂O₇²⁻, all four films performed comparably and can serve as specific fluorescent sensors for these analytes. Compared with powdered MOFs, these films are not only highly efficient, stable and recyclable but also portable and easy to operate. This device fabrication strategy lays the fundament for the application of the reported metal-organic frameworks in diverse areas such as environmental protection, pollution control, material innovation, and public health.</p> Graphical Abstract <p></p>