Imidazolium salts and derivatives have antitumor efficacy and toxic effects in different micro-organisms. In this study, an imidazolium bromide salt (NMI) was synthesized, and its antitumor potential was investigated by in vitro studies. Radiolabeling of synthesized NMI was carried out by iodogen method using I radionuclide. The yield of radiolabeling was determined as 98.5 ± 0.1%. After that, cytotoxicity and intracellular uptake studies were evaluated in various cell lines. The cytotoxicity of NMI was determined as 35, 20, 10, and 1 μm for HEK-293, PC-3, CaCo-2, and MCF-7 cells, respectively. In addition, the intracellular uptake of I-NMI was investigated in the cell lines, and the uptake was significantly found as 4 hr for MCF-7 and 6 hr for PC-3. In future studies, antitumor efficacy of I-NMI on tumor-bearing animal model might be studied in light of these results.