Pentathiepins fused to naphthalene and phenanthrene have been synthesized by a simple method. Ring size depends on the stability of generated products related to steric and electronic factors. Sometimes, delocalized pi-electron of polyarornatics shows synergistic effect on the stabilization of polysulfur rings. The structures of two polysulfides were also studied by X-ray crystallography and phenanthrene bearing C2S5 ring showed different solid-state properties than corresponding phenanthrene bearing C2S3 ring. (c) 2006 Elsevier Ltd. All rights reserved.