Cationic Solution and Solid‐State Emitters – Robust Imaging Agents for Cells, Bacteria, and Protists

A library of eight different cationic emitters with emission properties in solution and in solid‐state (solution and solid‐state emitters – SSSE) is presented. These compounds, bearing either ammonium or pyridinium groups, have been investigated regarding their photophysical properties as well as their potential application in biological imaging. Besides high quantum yields as well as a high degree of stability during the imaging process, it was additionally revealed that a broad range of biological targets can be addressed, such as different bacterial strains, human cells as well as protists. The reported SSSE approach employing the mentioned robust emitters for biological imaging, will contribute to a rapid and facile way to design and apply affordable emitters with outstanding properties. Additionally, these emitters will overcome the drawbacks of classical luminophores and agents featuring well‐known aggregation‐induced emission (AIE) or aggregation‐caused quenching (ACQ) properties. Be positive for imaging A series of luminescent cationic solution and solid‐state emitters have been synthesized and applied for bioimaging purposes. In addition to low toxicity and facile synthesis, these emitters revealed striking uptake into biological samples such as human cells, bacteria as well as protists with high contrast during the fluorescence microscopy.