A new series of the title compounds has been synthesised and their lethal and grosscns activities on the brain of albinomice investigated. The intermediate 2-aryl-3-(3-thio-4-oxo-thiazolidin-5yl)-methylenyl indoles (1–3) were prepared by the ‘Knoevenagel Condensation’ of 2-thio-4-oxo-thiazolidine with 2-aryl-indol-3-aldehydes. The aforesaid compounds (1–3) gave fifteen new title 2-aryl-3-(3-disubstituted aminomethyl 2-thio-4-oxo-thiazolidin-5yl)-methylenyl-indoles (4–18) by the ‘Mannich reaction’ with different secondary amines, utilising the thio-amidic active hydrogen at position-3 of thiazolidine ring. The structures of all the newly synthesised compounds have been assigned by their elemental analysis (C, H, N) and spectral studies (ir andpmr). In their pharmacological screenings, the compounds were found to be psychotropics and relatively nontoxic except one compound. Few of the tested compounds have induced writhing and showed effect on the body temperature.