Indole monomer was chemically polymerized to produce polyindole (PI) powder for use as a positive electrode material for lithium rechargeable batteries. Although the PI obtained was an oligomer with a low molecular weight corresponding to just 3 indole units, its electrochemical properties exhibited high d.c. electric conductivity comparable to that of the highly conducting polyaniline-LiPF6 or LiAsF6. A charge separation mechanism was also suggested to describe charge/discharge behavior of the oligo-indole (OI) protonated and/or lithiated in the Li parallel to OI battery. Moreover, the lithium rechargeable battery adopting the OI as a positive electrode showed good cycleability with a discharge capacity of similar to 55 mAh g(-1), which did not decay until after more than 100 cycles.