The new organocatalyst amine-iodine-iodide complex (DBUHI3) was prepared and used as a catalyst for the synthesis of 2,4,5-trisubstituted imidazoles in moderate to good yields from inexpensive, commercially available and eco-friendly ammonium acetate as a nitrogen source, 1,2-diketones and substituted aromatic aldehydes. The direct one-step multicomponent efficient synthesis was achieved with remarkable green advantages offered by this protocol such as short reaction time, the broad scope of a substrate, and simple experimental procedure.