The aim of this work is to investigate and qualify vitreous regions in new chalcogenide systems containing highly polarizable elements like S, Se, As, Sb, Bi, Pb and I. The sulfur based system, As2S3-Sb2S3-Bi2S3-PbI2, as well as the selenium containing glasses As2Se3Sb2Se3-PbI2 have been studied. Large vitreous regions have been defined in the both systems: sulfur and selenium. Indeed, several glass compositions can accept in the vitreous network a molar concentration near 50% of PbI2. Physical properties such as glass transition temperature, crystallization temperature, optical transmission, band-gap wavelength have been measured versus glassy compositions. (c) 2005 Elsevier B.V. All rights reserved.