1, 1-Ethylene-1H-azulenium tetrafluoroborate (1b) and its alkyl substituted derivatives, 6-t- butyl (1c) and 4-isopropyl-3, 8-dimethyl ones (1d), were synthesized starting from their corresponding azulenes by a three-step sequence which includes reduction, cyclopropanation and hydride abstraction reactions. The cation 1 b and its 6-t-butyl derivative 1c, generated in deuterated acetonitrile at− 20° C, were characterized by low- ...