Aromatic Polypyromellitimides were Prepared in two steps. Pyromellitic dianh ydride was added to the solution of an aromatic diamine in aprotic polar solvent, DMF. The reaction was conducted to obtain a viscous prepolymer, and the prepolymer was converted to insoluble polyimide by means of thermal method. Used aromatic diamines were 3,3''-diaminodiphenylether, 3,4''-diaminodiphenylether, 4,4''-diaminodiphenylether, m -phenylenediamine, and p-phenylenediamine. The 5 polypromellitimides prepared from the above diamines were investigated for solublity and thermal stability. These polymers were found to have the activation energies of thermal degradation in the range from 38 to 67 Kcal/mol.