Tropylium tetrafluoroborate is widely used in organic synthesis as a stable and easily handled source of the tropylium cation. Its primary application is in the formation of tropylium salts, which serve as intermediates in various chemical reactions. It is particularly useful in electrophilic aromatic substitution reactions, where it acts as a strong electrophile to introduce the tropylium group into aromatic systems. Additionally, it is employed in the preparation of charge-transfer complexes and as a catalyst or reagent in polymerization processes. Its stability and solubility in organic solvents make it a convenient choice for laboratory-scale and industrial applications.