We present preliminary results on various transport and photophysical properties of a novel soluble conjugated polymer based on Zn-porphyrin units edge-linked by acetylenic spacers. The basic optical transitions of the porphyrin unit are retained in the polymer and the lowest-lying absorption is strongly red-shifted, indicating substantial extended conjugation in the system. chi((3))(-omega;0,0,omega), as assessed from electroabsorption measurements, is very large. Charged and neutral excited states are investigated by doping studies, photoluminescence, photoinduced absorption, and spectroscopy of electric field-injected charges in metal-insulator-semiconductor devices. Field-effect transistors with the porphyrin polymer as the active semiconductor are used to investigate the conductivity and mobility of charge carriers and the influence of oxygen and solvents on the transport properties.