Polyimides are disclosed having a particular decree of imidization and acid and or anhydride functionality. A process for preparing polyimides, having reouced acid and/or anhydride functionality, using acid and or annydride blocking agent is disclosed. Blends of polyimides with other thermoplastic materials are also disclosed. When the acid and/or anhydride functionality of a polyimide is reduced or substantially eliminated, the resultant polyimide may exhibit altered miscibility ana compatibility with the thermoplastic polymers, improved weatherability characteristics, and a lower melt viscosity thereby ennancing the processability of the polyimide.