A heterocyclic fluorogenic linker, thiadiazole dicarboxylate (H₂tdz), offering diverse coordination modes has been utilized to synthesize two three-dimensional (3D) metal organic frameworks {[Cd₂(tdz)₂(4,4′-bpy)₂]·6.5H₂O}_n (1) and [Cu(tdz)(4,4′-bpy)]_n (2) from a one-pot self-assembly reaction under ambient conditions in high yields. MOFs 1 and 2 are structurally characterized by elemental analysis, FTIR and UV-Vis spectroscopy, single crystal and powder X-ray diffraction, and thermogravimetric analysis. Their single crystal molecular structures reveal that 1 contains a permanent pore along the b-axis with dimensions of 14.576 × 17.567 Ų while 2 forms a 3D two-fold interpenetrated structure with an extensively reduced pore size. The effect of interpenetration has been further elaborated by a comparison of their CO₂ uptake capacities at 263 K, 273 K and 298 K. The uptake value of CO₂ for non-interpenetrated 1 (24.8 cm³ g⁻¹) is much higher compared to that of interpenetrated 2 (5 cm³ g⁻¹) at 298 K. Furthermore, to obtain an insight into the adsorbate–adsorbent interaction owing to the presence of the polar thiadiazole moiety and polarizable CO₂ molecules, the isosteric heat of adsorption (Q_st) was calculated for 1 (29.1 kJ mol⁻¹) and 2 (23.4 kJ mol⁻¹). Thermal and chemical stabilities of 1 in water were ascertained by variable temperature powder X-ray diffraction (VT-PXRD) analysis. MOF 1 having a d¹⁰ metal center was utilized to harness the availability of nitrogen atoms in the tdz²⁻ linker for the selective sensing of nitrophenols in water with a detection limit for TNP as low as 1.4 ppm. Moreover, 1 is found to be stable and recyclable up to four cycles.