A series of new imidazolidineiminothione derivatives with various halogenated and alkylated aromatic substituents at N-(1) and at N-(3) was synthesized through the reaction of N-arylcyanothioformamides with arylisocyanate derivatives. Structure of imidazolidineiminothione derivatives were established based on spectroscopic IR, (1)H NMR, (13)C NMR, (1)H,(1)H-COSY, HSQC, (19)F NMR, MS and elemental analyses data. Evaluation of antitumor, antiviral, antibacterial and antifungal activities for the synthesized compounds were carried out to probe their activities. Most of the synthesized compounds displayed antitumor activity. The presence of 3,5-dichlorophenyl moiety at N-(1) and trichlorophenyl moiety on N-(3) (2f) resulted the highest cytotoxic activity. The presence of 9H-fluorenyl moiety on N-(3) resulted in the lowest cytotoxic activity. The antiviral screening displayed that 2d and 2f were markedly active against one or two viral strains. Compound 2d (3,5-dichlorophenyl moiety at N-(1) and 4-chlorophenyl moiety on N-(3)) showed 100% antiviral effect toward HAV. Compound 2f showed 96.7% antiviral effect toward HSV1 and 80.3% antiviral effect toward HAV. The antimicrobial activity suggested that all of the imidazolidineiminothione derivatives possess significant antimicrobial activity against most of the test organisms. Some imidazolidineiminothione derivatives showed MIC values of antibacterial and antifungal activities ranged from 0.78 to 6.25 μg/ml.