Electrochemical nano technology (ENT) is a promising field growing in strong connection with electrochemical microsystem technology (EMT). Some principles of EMT like characterization and localization of reactions can be transferred to ENT. Some other principles like mechanical motion, quantum effects or microfluidics differ and have to be separately discussed. Properties of the nanocell, the smallest electrochemical two-electrode cell, are discussed as example of a special tool of ENT. It is useful for the preparation of nano-scaled metal-insulator-electrolyte-structures (MIE-structures). The role of the EMT number for field-induced localizations is discussed with the Si/SiO2-system as an example. Lateral metal-insulator-metal-structures (MIM-structures) are prepared in the nanocell with the system Nb/Nb2O5/H2O as an example.