Are organic compounds good candidates to substitute rare earth materials in fluorescent applications?

The optical properties of some organic compounds in solution or embedded within suitable host matrices are reported and discussed in terms of their performances for possible applications in lighting, photonic or biomedicine. The aim of the paper is to briefly review the presence of rare earth elements in these fields and to enlighten the possibility of their substitution because of global market cost/effectiveness considerations. The easiness of green chemical synthesis and functionalization, the fluorescence tunability over the visible spectrum range of dye molecules and their fluorescence quantum efficiency promote organic compounds as promising good candidate to substitute rare earth materials.