The electronic state and structural configuration of the intercalated iodine species in stage-1, I-Bi2Sr2Can-1CunOx (n = l, 2), have been studied through polarization-resolved Raman and129I Mössbauer spectroscopy. The polarization dependence of the Raman spectra and the Mössbauer measurement confirmed the dominant species to be triiodide ions, I3-, with alignment of these linear molecules either along the a- or b-axis in the host crystals. Transport measurements such as thermoelectric power and Hall coefficient clearly indicated that hole carriers are doped into the CuO2 planes upon intercalation, by which Tc of the host superconductor is changed. Furthermore, based on resistivity measurements in a magnetic field, we suggest that the iodine intercalation leads to a decrease of the anisotropy both in normal and superconducting states, suppressing the extremely two-dimensional character of the Bi2Sr2Can-1CunOx systems. © 1994 Plenum Publishing Corporation.