Current–voltage characteristics under illumination of monochromatic light for metal-free tetrabenzporphyrin, metal-free triazatetrabenzporphyrin, and metal-free phthalocyanine in (indium–tin–oxide)/porphyrin/Al sandwich cells seem to show high-energy conversion efficiencies of 14&percent;, 7.7&percent;, and 5.5&percent;, respectively. However, according to the simultaneous measurement of both short-circuit photocurrent and transmittance of the aluminum electrode with time, the transmittance of Al linearly increases as the photocurrent flows into the external circuit. It is concluded that all photocurrents in the above cells arise from photoaccelerated corrosion of aluminum electrode and do not originate from conversion of light energy to electrical energy. ©1997 American Institute of Physics.