Herein, we report the synthesis and photophysical characterization of the novel tris(4-(2,2-difluoro-6-methyl-2H-1λ3,3,2λ4-dioxaborinin-4-yl)phenyl)amine trimeric probe (A2) via the reaction between triphenylamine (1), acetic anhydride, and BF3·OEt2 implying the twelve new bond formation in a one-pot manner. This highly fluorescent compound in solution (φ up to 0.91 at 572 nm) and solid state (φ = 0.24 at 571 nm) showed a better solvatofluorochromism than its analog monomeric A1 due to symmetry-broken charge transfer, which is consistent with high solvent dipolarity (SdP) response in Catalán's multiparametric regression. Notably, A2 had a high sensibility and selectivity for CN- or F- in solution (LODCN-/F- = 0.18/0.70 μM), and CN- can be discriminated from F- by the reaction of A2 with 3.0 equiv. of CN-. In addition, A2 was impregnated on filter paper to prepare test strips that were applied to naked-eye qualitative sensing of CN- or F-. Finally, the octupolar system in A2 allows for better action of two-photon excitation cross-section values when compared with that of the dipolar structure in A1. These findings provide further information for the design of new efficient two-photon absorption dyes.
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