-Vinamidinim salt can be converted via 1,5-dipolar cyclization into electronrich thiophenes, pyrroles, thiazoles and imidazoles. Diazaquinoneiminium salts react with nucleophiles to methylenepiperazines and dihydropyrazines. Donor-substituted 1,3,5,7-tetrazocines, cyclopentadienylim and aza(diaza )cyclopentadienylium salts, though formally antiaromatic, are stable compounds.