In connection with the investigations of tuberculostatic activity of arylthiosemicarbazides and arylthiosemicarbazones new 4-substituted thiosemicarbazides (I-XVIII) were synthesized. Condensation of these with aldehydes or ketones afforded the corresponding 4-substituted thiosemicarbazones (XIX-LVI). The attempted \u27acetylation of p-nitrobenzaldehyde-4-phenylthiosemicarbazone and o - chlorobenzaldehyde - 4 - phenylthiosemicarbazone gave besddes acetanilide N,N.-diacetyl-p-nitrobenzylidenhydrazine (LVII) ,and N,N-dia cetyl-chlorobenzylidenehydrazine (LIX) .The 4-substituted thiosemic arbazides and thiosemiearbazones were tested for their tuberculostatic activity