Novel organic-inorganic composite 1D nanostructures composed of carbonized conductive nanofibers and nickel nanoparticle chains were prepared by the combination of an electrospinning method from metal complex-containing polymer solutions and an ion-beam irradiation technique. The nickel nanoparticle chains were formed by self-assembly inside the carbonized nanofibers, which were characterized by STEM-HAADF observation and XPS spectroscopy. The existence of nickel complexes and the subsequent formation of nickel nanoparticles enhanced the electrical conductivities of carbonized nanofibers to reach above 0.5 S cm(-1) for the 6FDA-6FAP nanofibrous membrane containing 5.0 wt% Ni(acac)(2) after ion-beam irradiation at an ion fluence of 1 x 10(16) ions per cm(2).