Microwave-assisted treatment of various heterocyclic amides (benzodiazepinone, phthalazone) with TiCl4 in the presence of primary or secondary amines provides the corresponding amidines. In addition to the interest of the microwaves for this reaction, our study highlights the higher reactivity of the cyclic acetamide moiety compared to the cyclic benzamide moiety towards this TiCl4-mediated reaction.