Novel polyimides, copolyimides and molding compositions are prepared from novel dianhydrides such as tricyclo[6.4.0.0.sup.2,7 ] dodecane-3,6-diphenyl-1,8,4,5-tetracarboxylic acid dianhydride and tricyclo[6.4.0.0.sup.2,7 ] dodecane-1,8,4,5-tetracarboxylic acid dianhydride. The novel polyimides are useful as engineering plastics. The novel dianhydrides are useful for the preparation of the polyimides. Other dianhydrides can be mixed with our novel dianhydrides to make novel copolyimides useful as engineering plastics.