Photoinduced electron-transfer (PET) reactions represent a powerful methodology with widespread applications in the fields of organic and synthetic polymer chemistry. Within this literature, among the various surface coating methods, marine mussel-inspired adhesive bonding by polydopamine (PDA) coatings has attracted great interest. Although various procedures for PDA synthesis have been reported, they exhibit some limitations, such as requirement of acidic or basic conditions or strong oxidants. To address these issues, here we report a simple PET protocol for PDA production under UV, visible, and daylight irradiation using diphenyliodonium salt in the presence and absence of sensitizers. This new methodology provides future directions for surface coatings and bio-functionalization.