The current project is a study of the role of structural defects (intrinsic and impurity) on the luminescent and scintillation properties of crystals. The nature of scintillation efficiency losses in scintillators based on halide (BaF2 and NaI) and oxide (Y3Al5O12) dielectric compounds depends on the defects that are centers of trapping of charge carriers. Introduction of additional ions into host leads to crystal lattice changes and defects appearance. The presence of these defects may reduce or increase the efficiency of energy transfer to luminescence centers and makes worse or improve scintillation properties of crystals. The practical significance of the work is in the fact that the research results show the possibility of a directed change in the properties of alkaline and alkaline-earth halides and oxides by controlling their defects structure. This approach is the basis for similar researching for a wider range of dielectric systems.