Solvent-based deposition techniques for fabrication of organic field-effect transistors (OFETs) generally require orthogonal solvents for deposition of a conjugated polymer layer on a polymer gate insulator layer. Here, we found significantly reduced dissolution rate of the polymeric film in the same solvent after casting a homegeneous polymerization solution of para-bis(3-aminopropyl)hexaisobutyl-substituted T8 cage (1) with terephthalaldehyde. The limited dissolution rate in the solvent provided enough chance for fabrication of a regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) layer on the present polymer films without using an orthogonal solvent. The rheological properties indicate that physical interaction between the polymer chains provides the significantly reduced dissolution rate after the deposition onto a substrate without any cross-linking treatments.