Acylhydrazinecarbothioamides (2a,b) were synthesized by addition of 2-(5H-dibenzo[a,d][7]annulen-5-yl)acetohydrazide to different isothiocyanates. The new 1,2,4-triazol-3-thioles (3a,b) were synthesized by cyclization of new 2- acylhydrazinecarbothioamides (3a,b) in basic media. Alkylation of 1,2,4-triazole-3-thiols (3a-c) with ethyl bromide gave only S-substituted derivatives (4a-c). The structures of the synthesized compounds have been established on spectral data (IR, 1H-NMR and 13C-NMR spectroscopy) and elemental analysis. The cytotoxic effect of new compounds was evaluated using two alternative models on plant and invertebrate organisms.