A series of Co(II)−H 2 L coordination polymers were prepared with different auxiliary ligands, namely {5-{(anthracene-9-ylmethyl)-amino}isophthalic acid, bibp = 4,4′-bis(imidazolyl)biphenyl, bpy = 2,2′-bipyridine, bipd = 3,5-bis(1-imidazoly)pyridine, and bbibp = 4,4′-bis(benzoimidazo-1-yl)biphenyl), by a similar solvothermal method. X-ray diffraction analyses revealed that 1, 3, and 4 exhibit a two-dimensional (2D) structure, which further builds the threedimensional (3D) supramolecular architecture via the weakly interacting hydrogen bonds of C−H•••O, while 2 displayed a onedimensional (1D) double-chain architecture extended from two 1D zigzag chains by intermolecular hydrogen bonding interactions. The sensing experiments revealed that 1 and 2 can serve as either individual-and/or multi-responsive sensors to selectively detect Cr 3+ , Al 3+ , and Pb 2+ ions through the fluorescence turn-on effect, while 3−4 exhibited fluorescence turn-off sensing behavior for Fe 3+ ions. Moreover, 1−4 can effectively detect and recognize Cr 2 O 7 2− and CrO 4 2− due to their high selectivity and sensitivity for fluorescence quenching in aqueous solutions, and the sensing mechanism for various ions has been discussed.

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Various carcinogenic dyes in water bodies are difficult to degrade due to their stability to light and oxidants, causing extended pollution. In this study, MOF 1 ({[Co(tib)2]·(H2O)2·SO4} n ) and MOF 2 ({[Cu(tib)2]·(H2O)2·SO4} n ) (tib = 1,3,5-tirs(1-imidazolyl)benzene) were synthesized by the solvothermal method. MOFs 1 and 2 were successfully characterized by single-crystal X-ray diffraction (XRD) and powder X-ray diffraction (PXRD). Based on the structural characteristics of MOFs 1 and 2, we designed two cationic MOF material skeletons, namely, MOFs I and II ([Co(tib)2 2+] n and [Cu(tib)2 2+] n ), which were obtained by calcination in combination with the thermogravimetric curve to remove the free components in the lattice. As expected, MOFs I and II showed an excellent adsorption effect on sulfonic anionic dyes. Notably, the adsorption capacity of MOF I can reach 2922.8 mg g–1 for Congo Red (CR) at room temperature (RT). The adsorption process fits the pseudo-second-order kinetic model and Freundlich isotherm model. Moreover, zeta potential tests and quantum chemical calculations indicate that electrostatic interactions and hydrogen bond between the hydroxyl group on the sulfonic acid group and the N atom on the imidazole ring mainly promote the adsorption of CR dyes on MOF I. MOFs I and II are revealed as a promising novel adsorption material to remove hazardous organic aromatic pollutants with high efficiency in future endeavors.