The structure of fluorindine is established by nmr as the 5,14-dihydroquinoxalino[2,3-b]phenazine. The catalytic hydrogenation of 2,3-di(p-methoxyphenyl)pyrazino[2,3-b]phenazine2aleads to the 6,11-dihydro derivative4a. The electrochemical reduction in an hydroorganic medium furnishes4aand then the 1,4,6,11-tetrahydro derivative8a. In dry DMSO the voltammogram shows four monoelectronic reversible systems corresponding to the successive formation of a radical anion, dianion, radical trianion, and tetraanion. Thus2aappears as a new example of the very restricted class of compounds leading to tetraanions upon electrochemical reduction. The catalytic hydrogenation of 2,7-diphenylpyrazino[2,3-g]quinoxaline1aor the reaction of LiAlH4with 1,2,7,8-tetramethylpyrazino[2,3-g]quinoxaline1bleads to 1,2,3,4-tetrahydro compounds. The electrochemical reduction of1aand1bin hydroorganic medium leads successively to 1,4-dihydro and then to 1,4,6,9-tetrahydro compounds which undergo a further rearrangement. In dry DMSO1aand1bbehave differently from2a: one only observes two reversible monoelectronic systems.