Organic aromatic amines are widely used in various fields such as pharmaceuticals, pesticides, dyes, and tobacco smoke. The pollution of organic amines has become a problem that cannot be ignored, due to the extensive harmful effects on the environment and public health, which has become one of the most concerned frontier fields in the world. Identifying and microdetecting o-phenylenediamine (OPD), m-phenylenediamine (MPD), and p-phenylenediamine (PPD) using MOFs have rarely been reported. On the basis of the blue emission properties of Cu-TBDA constructed with 5,5'4(6-cliloro-1,3,5-triazine-2,4-diy1)bis(azanediyl))diisophthalic acid (H(4)TBDA) ligand, Cu-TBDA was studied primarily to identify and detect aromatic diamine family as a multifunctional chemical sensor. Interestingly, Cu-TBDA has a very high selectivity and sensitivity to OPD and MPD with a low limit of detection (5.00 mu M for OPD and 1.77 mu M for MPD). Especially for OPD, Cu-TBDA has a unique switching function for it. When the concentration of OPD is less than 9.1 x 10(-4) M, the fluorescence response of Cu-TBDA suspension exhibit enhanced. However, when the concentration of OPD is more than 9.1 x 10(-4) M, the emission intensity displays quenching phenomenon. Therefore, Cu-TBDA as a chemical sensor not only has recognition and detection functions for organic aromatic amines but also first exhibits turn-on and -off sensing behavior toward OPD.