Surface modification based on “grafting from” techniques provides a versatile tool for industry and science. In our research, a highly efficient and visible light sensitive (up to 450 nm) photoinitiator, which is based on germanium, was immobilised on the surface of spherically shaped silica nanoparticles (30 nm in diameter). We demonstrated that this species can be employed for a novel and unique cationic “grafting from” process: surface-initiated radical promoted cationic photopolymerization (SI-RPCP).