In the past ten years there has been a flurry of activity in the synthesis of new specialty polymers

largely as a result of the increased need for high technology materials. Interest is mainly shown in two distinctcategories of polymers: a) polymers which are used in very small quantities to fulfill critical needs as a part ofdevice systems

and b) high-performance engineering polymers which significantly extend their mechanicaland thermal properties for structural applications. Polyimides and their unparalleled versatility have captured the attention and imagination of scientists and engineers.This article describes some of the recent work done by the author's group on the rational design at the molecular level and the synthesis of polyimides that have unusual structures and novel properties.