The reactions of 4,5-dihydro[1,2,4]triazolo[3,4-c]benzo[1,2,4]triazines with aromatic aldehydes gave stable iminium salts which were deprotonated to give newazomethine imines. These new mesomeric betaines underwent 1,3-dipolar cyclization reactions to yield new tetra- and pentacyclic heterocycles. X-ray analysis and decoupling NMR experiments unambiguously supported the fact that these transformations