The paper reports the comparative voltammetric behaviour of 1,4-benzothiazi
no[2,3-b]-phenothiazine 1, 16H,18H-dibenzo[c, 1]-7,9-dithia-16,18-diazapent
acene 2 as well as of their copper salts and complexes with organic accepte
rs. The reversible redox systems are characteristic for one phenothiazine u
nit in the structure. Relationships between formal potentials and donor (DN
) or acceptor number (AN) of the Solvent are also included.