A new three-component photoinitiator system consisting of a dye, an iron arene complex, and a phenylglycine derivative was investigated by fluorescence quenching experiments and laser flash photolysis. The efficiency of a three-component system in photopolymerization reactions is higher by a two-fold factor compared to that of the two-component system. The first step of the photoreaction occurs between the dye and the iron arene complex. The iron arene complex reacts either with the singlet excited dye or with the triplet excited dye according to the nature of the dye. An electron transfer occurs in these systems. The mechanism was discussed in terms of the absence of the formation of a terminating radical in the three-component system.