Abstract 1-Dialkylaminomethylpyrroles are shown to behave in many respects like aminals. Acylation by an acid chloride, for instance, occurs normally at the amine-type N-atom rather than at the pyrrole ring. Spontaneous cleavage of the resulting quaternary acylammonium salts affords the 5-azoniafulvene ion (3). This higly reactive iminium ion, and its benzo- annellated analogue (4) can be trapped by electron rich aromatic compounds such as N- ...