The possibility of using colloidal silver and gold as condensors for electron storage in artificial photosynthesis has prompted the renewed interest in these areas. In this chapter, the authors discuss the role of light in the wet-chemical synthesis of metallic nanoparticles and how it affects the current synthetic models on nucleation and growth of such metal nanoparticles. Although they are aware of the works devoted to synthesis of non-noble metal nanoparticles in the presence of light, they limit their discussion to plasmonic nanoparticles. Their discussion culminates with the proposal of new synthetic models for more efficient and versatile fabrication of nanoparticles using light as an energy input. Wet chemical approaches for synthesis of metal nanoparticles may be classified according to two major mechanisms: nucleation/growth and autocatalytic reduction, so-called seeded-growth. The reducing agent in metal nanoparticle synthesis can be any molecule that can reduce the metal precursor into the zero-valent state.