Novel oxidative coupling polycondensation is developed. When bishydrazide is treated with oxone, poly(diacylhydrazine) (PDAH) is obtained. Although PDAH exhibits high thermal stability in air, PDAH is rapidly oxidized and degraded to the corresponding dicarboxylic acid upon treatment with sodium hypochlorite. Therefore, an oxidatively degradable high-performance polymer is obtained by oxidation, as presented by Kentaro Nagashima, Nobuhiro Kihara, and Yusuke Iino on page 4230. The first stage of the cover image indicates the oxidative coupling of hydrazide with oxone (persulfate anion) to form bishydrazide, releasing nitrogen and water. The second stage indicates the oxidation of polymer with hypochlorite anion to form dicarboxylic acid and nitrogen.