A series of conjugated aromatic polyoxadiazoles was prepared by cyclization with phosphorus oxychloride of the corresponding polyhydrazides. These last ones were obtained by solution polycondensation of 2-alkoxy-terephthaloyl dihydrazides with 2-alkoxy-terephthaloyl dichlorides. Homogeneous thin films of such a material were prepared by the spin-coating technique. Films spun on silica fused were characterized by spectroscopic analysis in the whole ultraviolet-visible-near infrared (UV-VIS-NIR) range (200-2500 nm). Spectra in transmittance show a peculiar and very interesting behavior of these materials: they absorb all the radiation in the UV-VIS range until 425 nm, where sharply the transmission becomes more than 90% until the IR range. Some films spun on silica fused were used as planar waveguides and studies on light propagation in these films were done. The optical constant (refractive index) and the film thickness has been measured using optical mode guiding. It has then been prepared a device consisting of the said polymer sandwiched between two electrodes on top of a glass substrate. The electron conductivity of the polymer, calculated by current-voltage measurements using Al as the electron injecting contacts, has been found to be higher than that of poly(p-phenylene-1,3,4-oxadiazole). (C) 2002 Elsevier Science B.V. All rights reserved.