The synthesis of controlled molecular weight semicrystalline polyimides based on 1,3-bis-(4-aminophenoxy)benzene (TPER diamine) and 3,3’,4,4’-biphenyltetracarboxylic dianhydride (BPDA), end capped with phthalic anhydride, is reported herein. The above polyimide henceforth referred to as TPER polyimide (M(n) = 20k, 30k) displayed excellent thermal stability, as evidenced by dynamic thermogravimetric analysis in both air and nitrogen atmospheres. This polyimide displayed a glass transition temperature of ca. 210 degrees C based on DSC measurements, and a melting temperature of 395 degrees C. A unique feature of this polyimide was the fact that quenching the polymer from the melt, even at very high cooling rates (ca. 200 degrees C/min), did not result in an amorphous polymer, implying very high crystallization rates from the melt. The subsequent melting endotherm was also shown to be extremely narrow, as evidenced by a sharp endotherm in the DSC trace, which was attributed to a narrow distribution of crystal thicknesses. On the basis of the results of the melting behavior of nonisothermally and isothermally crystallized samples, a process of melting/recrystallization has been shown to occur in the system during the DSC heating scan. This melting/recrystallization phenomenon has been shown to give rise to the observed multiple melting endotherms in the DSC scans of isothermally crystallized samples. The equilibrium melting temperature of this polymer estimated using a Hoffman-Weeks plot was shown to be 408 degrees C. The thermal stability of the TPER-based system has been investigated by monitoring the crystallization and melting response after residence in the melt at various times and temperatures. Melt time and temperature studies showed the exceptional thermal stability of the TPER polyimide versus corresponding results for the commercial polyimide "New TPI" and for a polyimide based on 1,4-bis(4-aminophenoxy)benzene and 4,4’-oxydiphthalic anhydride (TPEQ polyimide). Polyimide samples with amine end groups, as well as samples partially end capped with phthalic anhydride were shown to display distinctly lower thermal stability compared to phthalimide end-grouped samples. The improved behavior was demonstrated by melt rheological and crystallization experiments.