A series of substituted imidazoles have been synthesized under solvent-free condition by grinding 1,2-diketone, aromatic aldehyde, and ammonium acetate in the presence of molecular iodine as the catalyst. The short reaction time and easy workup make this protocol practically and economically attractive and are characterized by NMR spectra, X-ray, mass, and CHN analysis. Their antioxidant potential were evaluated using different in vitro antioxidant models namely, DPPH (1,1-diphenyl-2-picrylhydrazyl) radical, superoxide anion, and hydroxyl radical scavenging activities. Their antibacterial screening against Staphylococcus aureus, Escherichia coli, and Klbesiella pneumoniae and antifungal activity against Aspergillus niger, Aspergillus flavus, and Candida-6 were also evaluated. Among all, dimethoxyphenyl substituent at N3 of the imidazole derivatives exhibited the highest hydroxy and superoxide anion radical scavenging activities, whereas dimethoxyphenyl substituent at N3 and fluorophenyl at C2 of the imidazole derivatives exhibited the highest DPPH radical scavenging activity.