A facile and versatile solution-based approach was developed to prepare semiconductor metal oxide nanobelt-conducting organic polymer core-shell nano-composites. Well-defined nanobelts of several types of oxide nanobelts were combined with conducting polymer [polypyrrole (PPy) and polyaniline (PANi)] via in situ polymerization in aqueous solution to obtain a new type of inorganic-organic composite nanostructure. Samples were characterized by using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, electron energy loss spectra, high-resolution transmission electron microscopy, and ultraviolet-visible techniques. Electron energy loss spectra revealed the existence of C=C and C-N bonds in coating layers to prove the encapsulation of PPy or PANi. The red-shift of absorption band at high-energy was observed for PPy-encapsulated composites via ultraviolet-visible spectroscopy, and significant absorption band shifts were also encountered to PANi-encapsulated composites, which suggest possibilities of band-gap tuning of such metal oxide-conducting polymer composites to be applied especially in solar cell devices. However, the sacrifice of nanobelts-core led to hollow structures of PPy and PANi, which expands the synthetic strategies to prepare conducting polymer nanotubes. (c) 2005 Wiley Periodicals, Inc.