<p>A new series of (co)poly[(N-arylene diindolylmethane) ketone]s (FPNAIK-1–5) having a pendant clickable furyl group was synthesized through nucleophilic substitution polycondensation by varying molar proportions of renewable furfural-indole based monomer, i.e. 3,3'-(furan-2-ylmethylene)bis(1H-indole) and 3,3-diindolylmethane with 4,4′-difluorobenzophenone. ¹H-NMR, ¹³C-NMR, ¹³C-DEPT-NMR, Mass and FT-IR spectroscopy confirmed the chemical structures of the synthesized monomers and polymers. The inherent viscosities of all FPNAIKs were determined within the 0.42–0.45 dL/g, indicates formation of moderate molecular weights. The thermal stability of all FPNAIKs showed a T_d10% value under N₂ atmosphere in the range 450–470&#xa0;°C. UV–visible spectrum of FPNAIK showed λ_max at 355&#xa0;nm, and fluorescence spectral studies revealed light green emission. Cyclic voltammetry confirmed the electroactive behaviour of FPNAIK, highlighting their potential applications in optoelectronics devices. Post-modified (co)poly[(N-arylene diindolylmethane) ketone] (GPNAIK) was synthesized from FPNAIK-1 with aliphatic maleimide via Diels–Alder reaction. ¹H-NMR and FT-IR spectroscopy confirmed the post-modified GPNAIK chemical structure. This post-modified GPNAIK were soluble in polar aprotic solvents at room temperature. An X-ray diffraction study confirmed that all polymers are amorphous in nature. These research established furyl-indole based polymers as a sustainable approach towards the synthesis of high-performance materials that combine thermal stability, electroactivity, and optical properties for future optoelectronic technologies.</p> Graphical Abstract <p></p>