Substituted Maleimides: Self‐Reportable Linkers and Tags in Bioconjugation, Materials Science, and Nanotechnology

Substituted maleimides are customisable fluorescent linkers and probes with adaptable reactivity and optical properties. Their compact nature and tunability has led to their use in various applications. For example, their solvatochromic properties offer real‐time feedback on linking chemistry and environmental changes, essential for applications in material labelling, drug delivery, and nanoparticle functionalisation. This review focusses on developing, synthesising, and modifying substituted maleimides as environment‐sensitive fluorescent linkers and probes. It delves into their photophysical dynamics and strategic applications, highlighting their significant contributions to macromolecule conjugation and the development of self‐reporting materials. Substituted maleimides are a highly modifiable heterocyclic motif and represent a versatile class of site‐selective linkers characterised by their small size and customisable structures. This minireview encapsulates the evolution of substituted maleimides, detailing their synthetic pathways and specific mechanisms that govern fluorescence. The ongoing development of substituted maleimides aims to expand their applications as next‐generation self‐reportable linkers in bioconjugation, materials science, and nanotechnology.