Most of the photoinitiating systems (PIS) that are commercially available exhibit absorption spectra in the UV-blue region. There is a need to design new PIS that can be irradiated in the green to red region. In this paper, different approaches were investigated to increase the efficiency of PIS for free radical photopolymerization. The efficiency of photocyclic photoinitiating systems PCIS based on dye (PI) was first discussed. It was shown that the photopolymerization efficiency of the PCIS containing an amine (Co) and a triazine derivative (A) together with the dye is higher than that of the corresponding 2K system. A model was developed to predict the behaviour of such PCIS. Holographic recording underlines the differences in photoinitiating system reactivity, allowing diffraction efficiencies close to unity. A different approach consists in the synthesis of new dyads (S-T), based on squarylium dye (S) and substituted-triazine (T), which exhibit an intramolecular electron-transfer. The photochemistry of the dyad was compared to the corresponding unlinked systems (S+T). The efficiency of the dyads was demonstrated by measuring the maximum rate of free radical polymerization of acrylates in film. An excellent relationship between the rate of electron transfer and the rate of polymerization was found, evidencing the interest of this new approach to efficiently produce radicals under red light.