A new series of thermoplastic polyimides derived from 2,2-dimethyl-1,3-bis(4-aminophenoxy)prop (MD) and a new diamine 2-methyl-2-propyl-1,3-bis(4-aminophenoxy)propane (MPPD) have been prepared and characterized. These materials were selected on the basis of their potential to serve as low-cost matrix resins able to perform at 170 degrees C. They were synthesized from reasily available aromatic dianhydrides such as 3,3’,4,4’-benzophenonetetracarboxylic dianhydride (BTDA) and the above diamines. The glass transition temperature (T-g and crystalline melt temperature (T-m of these polymers containing flexible alkylene-dioxy units varied from 200 to 230 degrees C and from 300 to 375 degrees C, respectively. Polymers decomposed in air between 435 and 455 degrees C as witnessed by thermogravimetric analysis. Work was focused on the polymer prepared from 4,4’-oxyphthalic anhydride (ODPA) and MPPD, which had a T-g of 200 degrees C and could be readily melt processed below 305 degrees C.