Pyrylium tetrafluoroborate（Cat No.:L002937）is a salt consisting of a pyrylium cation (a six-membered aromatic ring with a positive charge on the oxygen atom) paired with a tetrafluoroborate anion (BF₄⁻). The pyrylium cation is an electron-deficient species, making it highly reactive and useful in various chemical reactions, such as electrophilic aromatic substitution. This compound is commonly used as an electrophilic reagent in organic synthesis, particularly in the preparation of aromatic compounds and in the formation of donor-acceptor complexes. Its stability is provided by the non-nucleophilic tetrafluoroborate anion, which also enhances solubility in polar solvents.