Various imidazolylsilane derivatives were synthesized by a trans-silylation procedure between 1-(trimethylsilyl)imidazoles and chlorosilanes. Among them, tris- and tetrakis(imidazol-1-yl)silane compounds reacted smoothly with free carboxylic acids to form the corresponding 1-acylimidazoles, which subsequently underwent condensation with amines to afford carboxamides in good to high yields. These results indicate that novel reagents containing silicon-imidazole linkage are effectively utilized as dehydrating reagents to form carboxylic acid derivatives from free carboxylic acids and nucleophiles under mild conditions.