The condensation polymerization of isophthalodihydrazide and diphenyl isophthalate affords poly(isophthaloylhydrazine-1,2-diyl). High-molecular-weight poly(5-tert-butylisophthaloylhydrazine-1,2-diyl) is prepared by the polycondensation of 5-tert-butylisophthalodihydrazide and bis(4-nitrophenyl) 5-tert-butylisophthalate in NMP at 100 degrees C. T-d of the poly(diacylhydrazine) is observed above 300 degrees C. No T-g is observed below T-d. The high-molecular-weight poly(diacylhydrazine) exhibits a film-forming ability. The poly(diacylbydrazine) decomposes on treatment with an oxidant such as sodium hypochlorite solution to obtain the corresponding carboxylic acid and nitrogen. However, poly(diacylhydrazine) was stable to oxygen and hydrogen peroxide even in the presence of transition metal ions. (C) 2008 Wiley Periodicals, Inc.