Dual anion and cation catalysis enabled by an ion-pairing photocatalyst†

Here, we report the first dual catalysis involving both anionic and cationic species of an ion-pairing photocatalyst. The key is the development of a photocatalyst composed of pyridinium cations and bromide anions, which upon irradiation facilitate hydrogen atom transfer and single-electron reduction events within their individual catalytic cycles. As a result, this type of ion pair acts as a multifunctional catalyst capable of independently promoting hydrogen transfer and cross-coupling reactions, thereby eliminating the need for any metals or external additives.