4-(4'-Aminophenyl)-1,2,4-triazolidine-3,5-dione (1) was reacted with 1,8-naphthalic anhydride (2) in a mixture of acetic acid and pyridine (3: 2) under refluxing temperature and gave 4-(4'-N-1,8-naphthalimidophenyl)-1,2,4-triazolidine-3,5-dione (NIPTD) (3) in high yield and purity. The compound NIPTD was reacted with excess n-propylisocyanate in N,N-dimethylacetamide solution and gave 1-(n-propylamidocarbonyl)-4-[4'-(1,8-naphthalimidophenyl)]-1,2,4-triazolidine-3,5-dione (4) and 1,2-bis(n-propylamidocarbonyl)-4-[4'-(1,8-naphthalimidophenyl)]-1,2,4- triazolidine-3,5-dione (5) as model compounds. Solution polycondensation reactions of monomer 3 with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), and tolylene-2,4-diisocyanate (TDI) were performed under microwave irradiation and conventional solution polymerization techniques in different solvents and in the presence of different catalysts, which led to the formation of novel aliphatic-aromatic polyureas. The polycondensation proceeded rapidly, compared with conventional solution polycondensation, and was almost completed within 8 min. These novel polyureas have inherent viscosities in a range of 0.06-0.20 dL g(-1) in conc. H2SO4 or DMF at 25degreesC. Some structural characterization and physical properties of these novel polymers are reported. (C) 2003 Wiley Periodicals, Inc.