This book has been dedicated to the study of doping of two types of liquid crystals with two kinds of materials: organic and inorganic one, both for optical properties. The first doping concerns doping of nematic liquid crystal (5CB) with organic dyes such Coumarin and oxazine 17, usually used for lasers. The fluorescence properties and energy transfer have been studied in 5CB and compared with isotropic solvents, where a study of solvatochromism of the dyes has been performed. We demonstrate that in nematic liquid crystals, resonance transfer dominates radiative transfer at a concentration of 0.3wt%. The second doping concerns doping of cholesteric liquid crystal film (E7+MLC6247) with gold nanoparticles. In this section, self-assembling of gold nanoparticles inside cholesteric liquid crystal at long range has been obtained.