Polyimides find applications in a wide range of areas, such as fuel cells, membranes, microelectronics, as they possess low dielectric constant, excellent thermal stability, good tensile properties and chemical inertness. Applications such as interlayer dielectrics and tape-automated bonding demand even lower dielectric constant. In this study, fluorinated monomers: 4,4′-(hexafluoroisopropylidene)bis[(4-aminophenoxy)benzene] (HFBAPP), 4,4′-(hexafluoro isopropylidene)dianiline (6FpDA), 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) were used in the synthesis of terpolyimide and its composites to increase the free volume. In addition covalent organic framework (COF-1) was synthesized and dispersed in different loadings into the solution of terpoly(amic acid) to get COF-1/terpolyimide composites. The pores of COF-1 and the voids formed between the polyimide chains and COF-1 could be filled with air having dielectric constant ~ 1 and further reduce the dielectric constant of the composites. The dielectric constant of the COF-1/terpolyimide composites reduced as the COF-1 content increased and attained a minimum of 1.96. The tensile properties reduced a little with the increase in COF-1 content. The terpolyimides and their composites were thermally stable up to about 520 °C.