Synthesis of nano-dimensional particles of cadmium sulfide in the pores of perfluorosulfonic membrane by means of the ion-exchange fixation of Cd2+ cations and the subsequent treating with gaseous hydrogen sulfide is carried out. As a result of gradual “step-by-step” accumulation of the guest substance monotonous downfield shift of the absorption bands in the visible spectrum is observed. In the luminescence spectra a set of bands is registered characterizing the dimensional distribution of small X-ray amorphous particles. Contrary to that one-step capsulation of cadmium sulfide by means of sulfidation of membrane with the content of Cd2+ ions close to the saturated state provides the formation of nano-dimensional particles of cubic structure. Their absorption band is maximally close in its position to that of the bulk CdS, and in the luminescence spectrum characteristic long-wave radiation with λmax 670 nm dominates. Optical properties of cadmium sulfide and their dimensional specific features are described considering the population of (Cd-S)-antibonding orbitals resulting from photoexcitation.