The regularities of formation of complex phases and regions of solid solutions possessing luminescent, photosensitive and thermoelectric properties were determined in the systems with the use of chalcogenides of arsenic, cadmium, indium and chalcogenides of REE. These materials are applied in semi-conductor technique, in particular, in electronic industry. The constitutional diagram has been plotted. The quaternary chalcogenide glassy compounds containing arsenic, cadmium, thallium and REE are used in infrared optics and photo electronics. Photo films obtained on their base using IR-radiation give photographic image in the darkness. By increasing metallization of chemical bond in   the region of glass formation and regular change of physical parameters have been decreased. The scientific bases of growth technology of monocrystals of complex chalcogenides of glassy and crystalline materials have been created. As a result of scientific achievements of workers of laboratory “Chemistry of rare earth elements” new photoelectric materials (As₂S₃)_1-x(YbS)_x and (As₂Se₃)_1-x (YbSe)_x have been obtained. The results have been confirmed by certificates of authorship. On the basis of lead telluride an effective thermoelectric material, working at a temperature range 500-1000K, has been obtained. The patent has been received for this work.