The endeavors accomplished in this book have been intended at producing Red Green Blue emission (and thus white light generation) in organic hosts viz. rare earths doped in polymers. Both singly and doubly doped RE ions have been studied after doping them in polymer films. Increasing the luminescence intensity in a polymeric host is a critical aspect and is interesting from scientific point of view. It is found necessary to add certain organic ligands to the RE ions before putting them all into the polymer host. Thus, RE(Sal)3Phen complexes have been synthesized in which multicolor emission is observed in the sensitized samples on UV excitation and this can be tuned to produce white light through an adjustment of the relative concentrations of the dopants.