Polyimide materials with several kinds of mechanical properties have a great potential to use in aviation and space technology. One of these kinds of polyimide materials is poly(imide siloxane) copolymers. By this work, we also aimed to get flexible substrates in order to use as substrates in solar energy technology. Randomly segmented Poly(imide siloxane) and poly(urethane siloxane) block copolymers were produced based on benzofenon-3,3’,4,4’-tetracarboxylic dianhydride (BTDA), 4,4’-oxydianiline (ODA) and bis(3-aminopropyl) polydimethlysiloxane (APPS). The ODA and BTDA are the hard segments, APPS and BTDA are the soft segments in the structure. Many kinds of these copolymers could be produced by adjusting the soft and hard segment lengths. Poly(imide siloxane) block copolymers were insoluable in many organic solvents.