Novel naphthalimide derivatives (or naphthalic anhydride derivatives) have been prepared and combined with an iodonium salt, <i>N</i>-vinylcarbazole, amines or 2,4,6-tris(trichloromethyl)-1,3,5-triazine to produce radicals and cations upon exposure to low intensity blue lights (e.g., a household blue LED bulb). The photochemical mechanisms are studied by electron spin resonance spin trapping, fluorescence, cyclic voltammetry, laser flash photolysis, and steady state photolysis techniques. The naphthalimide derivatives (ND4) or the naphthalic anhydride derivative (ND10) based photoinitiating systems are particularly efficient for cationic, radical and thiol–ene photopolymerizations; the synthesis of interpenetrated polymer networks IPNs can...