Carbon nanofibers of 50–500nm diameter and several micrometer length were synthesized by high-temperature pyrolysis of dihydro-2,5-furandione (C 4 H 4 O 3 ) in the temperature range of 600–980°C. The formation of both graphitic and non-graphitic structured carbon fibers was observed in high-resolution transmission electron microscope. The Raman spectra of the samples showed the presence of both the D and G bands of varying intensity and sharpness. The low-temperature electrical transport studies on the samples have shown interesting metal–insulator transitions. The films showed variable range hopping conduction in the insulating regime and power law behavior in the critical regime at low temperatures.