Figure 1.

a) Schematic representation of the fluorescence turn‐on mode of action and the portable strategy for the detection and discrimination of nitrite. b) The Schematic illustration of (i) the regulation of the fluorophore binding at the para‐, meso‐, and ortho‐positions of the aniline moiety, and (ii) the corresponding maps of the electrostatic potential surfaces of para‐BT, meso‐BT, and ortho‐BT, and (iii) the corresponding fluorescence spectra of the probes, probes under acidic conditions, and probes after the detection of nitrite, respectively. c) Proposed detection mechanism of ortho‐BT toward nitrite. d) Calculated electron‐density distribution and corresponding energy diagrams of the main molecular orbitals of ortho‐BT and the reaction products.