<p>Dopamine-based adhesives offer strong, versatile adhesion through diverse interactions but are limited by slow, poorly controlled oxidative polymerization and dopamine’s inhibition of radical polymerization. We present an efficient photochemical strategy for in-situ fabrication of high-performance polydopamine-containing hydrogels with instant wet adhesion. By integrating a scalable synthesis of a protected dopamine derivative with rational photochemical design, we enable simultaneous, light-controlled oxidative and radical polymerizations, forming interpenetrated hydrogel networks within seconds. The resulting tough adhesives exhibit high polydopamine content and strong adhesion across diverse wet and dry substrates, outperforming conventional polydopamine-coated systems. This rapid, light-driven process is compatible with extrusion-based 3D printing, allowing spatially programmable adhesion and the creation of complex biomimetic architectures. Furthermore, the instant, robust adhesion enables integration of flexible electroluminescent devices that remain stable under large deformations. This work establishes a versatile platform for rapid, programmable adhesion in soft electronics and biointerfacing systems.</p>