Novel 1-N-pyrazolinyl thiocarboxamides, 5-(3,4-Dimethoxyphenyl)-3-[2-(3, 4-dimethoxyphenyl)- ethenyl]-2-pyrazoline-1-thiocarboxamide (1b); 5-(4-Chloroyphenyl)-3-[2-(4-chlorophenyl)- ethenyl]-2-pyrazoline-1-thiocarboxamide (2b) and 5-p-Tolyl-3-(2-p-tolyl-ethenyl)-2-pyrazoline- 1-thiocarboxamide (3b) were synthesized from their corresponding α, β-unsaturated dienones, 1, 5-bis (3, 4-dimethoxyphenyl)-penta- 1, 4-dien-3-one (1a ), 1, 5-bis (4-chlorophenyl) penta-1, 4- dien-3-one (2a), 1, 5-bis (4-methylphenyl)-penta-1, 4-dien-3- one (3a) and thiosemicarbazide in the presence of catalytic amount of conc. hydrochloric acid respectively. The structures of these compounds were assigned by FT-IR, 1H- and 13C-NMR, DCI-MS and elemental analysis. The in vitro cytotoxicity of these compounds were evaluated against human cancers: breast (MCF7), lung (NCI-H460), CNS (SF-268) cell lines; antibacterial in (E. coli, S. viridans, S. epidermatis, B. subtilis) and antifungal in C. albicans, and compared with the standard drugs, chloramphenicol and Fluconozole. These compounds showed moderate to high antibacterial and antifungal activity in different species as compared to standard drugs. However, negligible cytotoxic properties were found against three cancerous cell lines. These compounds hold potential for their use in anti-infective agents also.