Abstract:Immunoactive ionic liquids (2-hydroxyethyl) ammonium 1-R-indol-3-ylsulfanyl-acetates HNwere synthesized by the reaction of (2-hydroxyethyl)amines with indol-3-ylsulfanylaceticor 1-benzylindol-3-ylsulfanylacetic acid. 1: R 1 = R 2 = CH 2 CH 2 OH, R 3 = H; 2: R 1 = СН 3 ,R 2 =CH 2 CH 2 OH, R 3 = H; 3: R 1 = R 2 = CH 3 , R 3 = H; 4: R 1 = R 2 = CH 2 CH 2 OH, R 3 = СH 2 С 6 Н 5 ; 5: R 1 = СН 3 ; R 2 = CH 2 CH 2 OH; R 3 = СH 2 С 6 Н 5 . The structure of each compound was elucidated by IR, NMR 1 H, 13 С, and 15 N techniques and their composition was confirmed by elemental analysis. The crystal structure of tris-(2-hydroxyethyl) ammonium indol-3-ylsulfanylacetate was investigated by X-ray diffraction analysis. Immunoactive properties of the title compounds were screened.