Background and Objectives. The TlGaSe2 and TlInS2 monocrystals are the А3В3С6 2 type ternary semiconductor compounds. Studies of TlGaSe2 and TlInS2 materials are carried out quite intensively due to the uniqueness of their optical and electrophysical properties and significant prospects for their practical use. At the same time, information about the effect of specific doping impurities on the properties of such materials is insufficient and often contradictory.