The ID hierarchical macroporous/mesoporous carbon nanofibers were prepared via electrospinning using PAN as carbon precursor and commercially available nano-CaCO3 as dual purpose template. During the carbonization process, nano-CaCO3 template decomposed and released CO2 to develop mesopores, and macropores were generated by subsequent acid removal of the as-formed CaO nanoparticles. This method is facile and low cost, allowing high-yield production of 1D hierarchical porous carbon nanofibers. The unique macro-/mesoporous structure of the nanofibers makes them a good support for anchoring palladium nanoparticles; the as-prepared catalyst shows high activity in various Suzuki cross-coupling reactions.