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In the present work, 3,3′-(butane-1,4-diyl)bis(1-methyl-1H-imidazol-3-ium) dichloride ([C₄(MIm)₂]·2Cl) and 3,3^′-(butane-1,4-diyl)bis(1-methyl-1H-imidazol-3-ium) hydrogen sulfate ([C₄(MIm)₂]·2HSO₄) were prepared via adequate, solvent-free methods and characterized using FT-IR, ¹H NMR, ¹³C NMR, and potentiometric titration techniques. These reagents were investigated in the synthesis of 5-arylidene (thio)barbituric acids, 2-arylidene malononitriles, 4H-pyrans, and pyrano[2,3-d] pyrimidineones, and their catalytic activities were compared in the promotion of these reactions. Based on the obtained results, we found that [C₄(MIm)₂]·2Cl showed more catalytic efficiency where a basic or weak acidic media is needed. In contrast, [C₄(MIm)₂]·2HSO₄ is a powerful catalyst in reactions needing acidic catalysts to enhance the reaction rate. Using these reagents, the products were formed under mild and eco …