Most of the human bacterial infections are associated with the biofilm formation and the natural tolerance of biofilms to antibiotics challenges treatment. Because of their low immunity, cancer patients are especially susceptible to bacterial infections. Compounds with anti-biofilm activity could therefore become a useful adjunct to chemotherapy, in particular if they also show antiproliferative activities. Taking this into consideration and as a result of our continuous interest in 2-aminoimidazole derivatives, we have designed and synthesized a series of novel polysubstituted 2-aminoimidazoles (20a-x). The compounds were evaluated against a panel of three bacterial strains for their biofilm and planktonic growth inhibitory activity and most of them show promising results. Furthermore, the synthesized compounds were evaluated against various cancer cell lines and almost all the compounds were found to possess potent antiproliferative activity. The substitution pattern at the C-4 position and the aryl carboxamide ring at the N-1 position have major effects on the biofilm inhibitory and antiproliferative activity. Especially, the introduction of a p-methyl group at the carboxamide ring remarkably enhances both the anti-biofilm and antiproliferative activity. The two most potent compounds (20i &20r) were further studied for their antiproliferative activity and a flow cytometer-based cell cycle experiment was performed, which revealed their capability to induce G2/M phase cell cycle arrest. Based on these results, these two new compounds having potential to target both cancer proliferation and microbial biofilms might be used in single drug monotherapy.