Herein, a N-rich metal–organic framework (MOF) with four kinds of cages, Zn4(ade)2(TCA)2(H2O) (NENU-1000, Hade = adenine, H3TCA = 4,4′,4″-tricarboxytriphenylamine, NENU = Northeast Normal University), was prepared by the mixed-ligand strategy. Cationic dyes can be selectively absorbed by NENU-1000 at proper concentrations, but not neutral and anionic dyes, which perhaps can be assigned to the N-rich neutral framework of NENU-1000. When NENU-1000 was introduced to a relatively lower concentration of cationic dye solutions (e.g., rhodamine B or basic red 2), the colors of these systems faded quickly. Furthermore, the faded solutions can be used for the detection of methanol and other small alcohol molecules with either the naked eye or common UV–vis spectra. The effect of the length of carbon chain, the position of the −OH group, and the number of the hydroxyl group of the alcohols was explored for the color development rate. In addition, the performance of NENU-1000 in iodine sorption and release was also studied.

Heavy metal pollution has become a worldwide concern of environmental problems. The replacement of partial Ti­(IV) centers with Eu­(III) or Tb­(III) yielded a couple of lanthanide­(III)-modified MIL-125­(Ti) materials, MIL-125­(Ti-Ln) [Ln = Eu­(III) or Tb­(III)]. MIL-125­(Ti-Ln) series were explored as fluorescent probes toward a series of metal ions based on the fluorescence properties of lanthanide­(III) centers. Heterometallic MIL-125­(Ti-Ln) series exhibited highly selective fluorescence quenching responses toward Cu­(II) and Fe­(III) ions. Moreover, the possible mechanism of fluorescence quenching was also studied.