The comparison of the data on the preparative electroreduction of 9-nitroanthracene in the mixtures of DMF-H2O was performed for the potentials of the first and second stages. It was shown that the protonation of the anion radicals of 9-nitroanthracene by water has virtually no influence on the course of their dimerization up to the content of the H2O in the DMF equal to 50%. The sharp change in the ratio of the electrolysis products under the conditions of the two-electron ER of (I) when water is present in the solvent is explained by the high rate of protonation of the dianion of 9,9′-dinitro-9,9′, 10,10′-tetrahydro-10,10′-bianthryl by water and the subsequent reduction of this hydrodimer. The PMR spectra of the cis and trans isomers of 9,9′-dihydroximino-9,9′,10,10′-tetrahydrobianthryl, which are formed by the reaction of the dimeric dianion with MeI and the subsequent thermal decomposition of the nitron ether, were studied.