Abstract In Canada the systematic investigation of organic semiconductors started in the mid 1950's. This review of the contribution of Canadian scientist to the field of organic semiconductors will be limited to discussing semiconducting properties of organic materials like electrical conductivity, carrier transport, and photoconductivity. Substantial spectroscopic work on organic semiconductors has been performed including optical spectroscopy (absorption, reflectance, luminescence, Raman), NMR, and ESR. Here spectroscopic measurements will only be covered inasmuch as they illuminate semiconductive material properties. Significant work has also been reported on organic xerographic photoreceptors and photovoltaic solar cells. This work will be covered to the extent of contributing to our understanding of electrical properties and material parameters in organic semiconductors. In recent years electrical properties of polymers have also attracted significant attention. These developments, however, are outs...