An　effective　synthetic　route　has　been　reported　to　prepare　N/B　co-doped　hierarchical　carbon　nanofibers　(NB-HCNFs)　as　free-standing　electrodes　for　high-performance　supercapacitors.　Zeolitic　imidazolate　framework　(ZIF-8)　nanoparticles　were　embedded　into　polyacrylonitrile　(PAN)　through　electrospinning　to　obtain　PAN/ZIF-8　nanofibers.　Tannic　acid　(TA)　acted　as　a　coating　layer　for　PAN/ZIF-8　to　generate　hollow　ZIF-8　core　structures　within　the　fiber　and　an　intermediate　to　coordinate　with　1,4-benzenediboronicacid　(BDBA).　After　carbonization,　the　obtained　flexible　N/B　co-doped　hierarchical　porous　carbon　nanofibers　were　used　as　free-standing　electrodes　for　supercapacitors.　Thus,　unique　nanostructure　and　the　existence　of　heteroatoms　could　offer　remarkably　improved　electrochemical　properties　with　a　high　specific　capacitance　(288.2 F g　−1　at　a　current　density　of　1 A g　−1　)　and　good　cycling　stability　(96.9%　capacitance　retention　over　8000　cycles　at　10 A g　−1　).　In　addition,　the　NB-HCNFs　films　were　assembled　into　symmetric　supercapacitors,　which　displayed　a　high　energy　density　and　excellent　stability　(99.7%　capacitance　retention　after　8000　cycles　at　10 A g　−1　).　The　synthetic　method　might　provide　an　effective　and　facile　strategy　to　prepare　a　variety　of　hierarchical　doped　carbon　nanomaterials　for　energy　storage.　©　2019,　The　Minerals,　Metals　&　Materials　Society.