Despite their unique physical properties and diverse applications in materials science, poor solubility of polycyclic aromatic hydrocarbons (PAHs) limits further fine-tuning and investigation of these systems. Herein, we report a sulfoniumization strategy to solubilize and functionalize a diverse range of PAHs in a one-step protocol by the use of a triethylene glycol ether-substituted diaryl sulfoxide. While mono-sulfoniumization is generally observed, modification of the reaction conditions towards favoring the bis-sulfoniumization is shown. The downstream applicability of the resulting PAH sulfonium salts is validated by a series of post-functionalization reactions that include C–C and C–heteroatom bond formations, while their application in annulative π-extension (APEX) was showcased for the synthesis of tetra-tert-butylquaterrylene from perylene. The red-shifted absorption and fluorescence, along with high water solubility of the PAH sulfonium salts, enabled their application in bioimaging, where they demonstrated selective mitochondrial staining without cytotoxicity.
