A new Ni coordination polymer [Ni(MIP)(BMIOPE)]_n (1) was constructed (BMIOPE = 4,4′-bis(2-methylimidazol-1-yl)diphenyl ether, and H₂MIP = 5-methylisophthalic acid), possessing two-dimensional (2D) twofold parallel interwoven net structure with a 4⁴∙6² point symbol. Complex 1 has been successfully obtained based on mixed-ligand strategy. The fluorescence titration experiments revealed that complex 1 could act as multifunctional luminescent sensor to simultaneously detect UO₂²⁺, Cr₂O₇²⁻ and CrO₄²⁻, and NFT (nitrofurantoin). The limit of detection (LOD) values for complex 1 are 2.86 × 10⁻⁵, 4.09 × 10⁻⁵, 3.79 × 10⁻⁵ and 9.32 × 10⁻⁵ M for UO₂²⁺, Cr₂O₇²⁻, CrO₄²⁻ and NFT. The K_sv values are 6.18 × 10³, 1.44 × 10⁴, 1.27 × 10⁴ and 1.51 × 10⁴ M⁻¹ for NFT, CrO₄²⁻, Cr₂O₇²⁻ and UO₂²⁺. Finally, the mechanism of its luminescence sensing is studied in detail. These results manifest that complex 1 is a multifunctional sensor for sensitive fluorescent UO₂²⁺, Cr₂O₇²⁻, CrO₄²⁻ and NFT detection.

By using a semi-rigid tripodal ligand 5-(4-carboxybenzyloxy)isophthalic acid (H₃L) and lanthanide metal ions (Nd³⁺, Tb³⁺), two novel lanthanide metal–organic frameworks, namely, {[Nd₂L₂(DMF)4] DMF}_n (1), and {TbL(DMF)(H₂O)}_n (2), were synthesized under mild solvothermal conditions and structurally characterized by X-ray single crystal diffraction. Compounds 1 and 2 are isostructural, in which L^3– ligands linked dinuclear lanthanide metal–carboxylate units to form non-interpenetrated 3D network with (3,6)-connected topology. Luminescent investigations reveal that compound 1 displays the near-infrared emission at room temperature, and compound 2 can be employed as selective probe for Cr₂O₇²⁻ anion in aqueous solution based on luminescence quenching. Moreover, compound 2 exhibits catalytic activity for cyclo-addition of CO₂ and epoxides under relatively mild conditions.