Apart from numerous applications, for example in azo dye precursors, explosives, and industrial processes, the nitro group (−NO₂) appears on countless molecules in photochemical research owing to its unique characteristics such as a strong electron‐withdrawing ability and facile conversion to the reduced substituent. Although it is well known as a fluorescence quencher, fluorescent chromophores that contain the nitro group have also emerged, with 3‐nitrophenothiazine being recently reported to have 100 % emission quantum yield in nonpolar solvents. The diverse characters of nitro‐containing chromophores motivated us to systematically review those chromophores with nitro substituents, their associated photophysical properties, and applications. In this Review, we succinctly elaborate the advance of the fluorescent nitro chromophores in fields of intramolecular charge transfer, fluorescent probes and nonlinear properties. Special attention is paid to the rationalization of the associated emission spectroscopy, so that the readers can gain insights into the structure‐photophysics relationship and hence gain insights for the strategic design of nitro chromophores.

中文翻译：

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含硝基的荧光发色团：相对未开发的发射性质。

除许多应用（例如在偶氮染料前体，炸药和工业过程中）外，硝基（-NO ₂）由于其独特的特性（例如强大的吸电子能力和易于转化为还原的取代基）而出现在光化学研究中的无数分子上。尽管众所周知它是荧光猝灭剂，但也出现了含有硝基的荧光生色团，最近有报道称3-硝基吩噻嗪在非极性溶剂中具有100％的发射量子产率。含硝基生色团的不同特征促使我们系统地审查那些具有硝基取代基的生色团，其相关的光物理性质和应用。在这篇综述中，我们简要阐述了荧光硝基发色团在分子内电荷转移，荧光探针和非线性性质领域的进展。