A series of novel copolyimides have been synthesized from three commercially available dianhydrides and two diamine monomers containing the tetrahydro [5] helicene unit. Some of the copolyimides were soluble in common organic solvents such as 1,1,2,2-tetrachloroethane, N,N-dimethylacetamide, and N-methyl-2-pyrrolidinone. Molecular modeling was used to explain the enhanced solubility of the presented polyimides, based on structural features of the tetrahydro [5] helicene monomeric units. The onset temperatures for 5% weight loss for these polyimides, as assessed by thermogravimetry, were above 430 degrees C in nitrogen. Inherent viscosities of the obtained polyimides were above 0.36 dL/g.