CNFs by absorption-swelling technique using thiourea as the precursor followed by calcination at 500 °C for 1 h and 850 °C for 2h in Ar environment . Thus, the N, S co-doped CNFs got the atomic percentage of sulphur and nitrogen analysed from XPS were found to be 1.02 and 6.9%, respectively. the specific capacitance of N, S co-doped CNFs derived from the GCD at 1 A g -1 in 6 M KOH solution found to be 202 F g -1 which is substantially larger compared % shown the excellent specific capacitance of 182 F g -1 at 1 A g -1 in 6 M KOH solution by two-electrode system . The increment in capacitive behaviour is attributed to not only the existence of mesoporous structure but also the contribution from the doped heteroatoms. The relative contents of nitrogen, phosphorus and oxygen estimated from XPS analysis of ACF-10.3 wt% PDPP are found to be 4.14, 0.45 and 13.32 at. %, respectively. It has been found that the drastic decrease in SBET was observed from 814.2 to 12.6 m 2 g -1 when 3.9 wt. % of PDPP added into ACF. If the content of PDPP increases then the SBET also enhances and attained the maximum value of 130.6 m 2 g -1 where 10.3 wt% of PDPP was utilized. Furthermore, the ACF-10.3 wt% PDPP has demonstrated the good cycling stability with 88% retention of capacitance from its initial value after 10000 cycles and the three symmetric flexible device in series lighted a red LED and displayed in Fig. and, respectively.