<p>In this study, a magnesium metal‒organic framework (Mg-MOF) was synthesized using mixed ligands such as trimesic acid and glutaric acid. Different characterization techniques, such as FTIR, FESEM, EDX, XPS, XRD, HRTEM, BET and TGA, were used to analyze the synthesized Mg-MOF. Rietveld analysis of Mg-MOF has provided information about monoclinic structure. The Mg-MOF exhibited strong fluorescence quenching in the presence of Cd²⁺, Pb²⁺, Hg²⁺, and organic solvents over a broad concentration range (6.125 µM to 0.002 µM). The limit of detection (LOD) was calculated to be 0.875 µM for Pb²⁺, 0.677 µM for Cd²⁺ and 0.177 µM for Hg²⁺ ions. In solvent sensing, the limit of detection (LOD) was 0.11 µL for CS₂ and 42 µL for 2-nitroaniline. The time resolved fluorescence analysis and Stern-Volmer behaviour indicated dynamic mechanism for Hg²⁺ ions and mixed static-dynamic contributions for the Pb²⁺ and Cd²⁺ ions. The relevance of Mg-MOF in environmental monitoring applications is highlighted by its overall strong potential as a dual-function, turn-off fluorescent sensor for both organic solvents and heavy metal ions.</p>