Abstract2,4‐Diphenyl‐6‐(3‐maleoyliminophenyl)‐3,4‐dihydro‐s‐tetrazin‐1(2H)‐yl (6) was synthesized and anionically polymerized with a catalytic amount of sodium 1,4‐dihydro‐1,4‐naphthalenediide, with a conversion up to 96%. The polymer was a dark green powder with a content of radical groups of about 58% (based on unit mol), and its relative molecular mass was about 4 800, correspond