On the basis of data of 13C and 1H NMR and IR spectroscopy, it was shown that 2-benzothiazolylhydrazones of aliphatic aldehydes were in solution as a mixture of E and Z isomers, and hydrazones of aromatic aldehydes were in solution only as E isomers. All investigated compounds existed in solution mainly in an amino tautomeric form, and the content of the imino form did not depend on the nature of the aldehyde fragment.