The photovoltaic properties of meso-tetraphenylporphyrin chromium(III) and manganese(III) (CrTPPCl and MnTPPCl) have been studied with solid thin films between two optically transparent electrodes. It is shown that the photoelectric effect of light beams correspond to the Sorer band and Q bands. With the help of the principle of field effects, the photovoltaic effect under an external alternating electric field of porphyrins is investigated. Due to a difference in electronic configuration, metalloporphyrins with different central ions exhibit a particular photovoltaic response under an external electric held.