2-[Bis(4-amino(nitro)phenyl)aminomethyl]-9H-thioxanthene-9-ones and their S-oxide derivatives have been synthesized, and their electrochemical reduction (ECR) in N,N-dimethylformamide (DMF) and MeCN has been studied by cyclic voltammetry (CV). The thioxanthene-9-one group [Th(O)S] and thioxanthene-9-one S-dioxide group [Th(O)SO2] determine the first one-electron peak potentials of 2-[bis(4-aminophenyl)aminomethyl]-9H-Th(O)S/Th(O)SO2. The first peak potentials of the corresponding dinitro compounds are determined by the ratio of reduction potentials of bis(4-nitrophenyl)amino and 9H-thioxanthene-9-ones moieties. Radical anions (RA) of the synthesized compounds have been obtained by ECR in DMF and MeCN and characterized by EPR spectroscopy together with DFT calculations at the (U)B3LYP/6-31 + G/PCM level of theory. Th(O)S and Th(O)SO2 groups are thermally stable up to 270 °C. The synthesized 2-[bis(4-aminophenyl)aminomethyl]-9H-Th(O)S/Th(O)SO2 are electrochemically active monomers for subsequent synthesis of the corresponding electroactive polyimides with thioxanthene-9-one based pendant groups for their applications in the design of nonvolatile memory storage devices. The pendant groups are characterized by low redox potentials and reversibility towards electron transfer.