Truxene‐Based Click Polymers for Fluorescent Detection of Nitroaniline Pollutants in Organic and Aqueous Media

ABSTRACT Two truxene‐based porous polymers incorporating dibenzothiophene dioxide units are synthesized via Cu(I)‐catalyzed azide–alkyne cycloaddition and evaluated as fluorescence sensors for nitroanilines in 1,3‐dioxolane and water. The polymers differ in alkyl chain length on the truxene methylene units (methyl vs hexyl), which strongly influences fluorescence behavior and porosity. Both exhibit similar absorption profiles, while TX(C6)DBTO shows a much larger BET surface area and retains fluorescence in the solid state and in water, unlike TX(Me)DBTO. This stability is attributed to steric hindrance from hexyl groups, which disrupt packing and suppress aggregation, as supported by single‐crystal data of its halogenated precursor. Both polymers display selective quenching toward 4‐nitroaniline (p‐NA) and 2,6‐dichloro‐4‐nitroaniline (DCN) in 1,3‐dioxolane, achieving micromolar detection limits. Time‐resolved fluorescence measurements confirm that quenching is not associated with energy transfer processes, but rather with the inner filter effect, consistent with the strong spectral overlap between analyte absorption and polymer excitation bands. TX(C6)DBTO preserves sensing performance in water, offering a robust, metal‐free platform for detecting nitroaniline‐based pollutants under environmentally relevant conditions.