The electrical and NO(2)sensing properties of a series of porphyrin derivatives (PPC12, PPC16, ZnPPC12) were studied within wide temperature range from 293 to 423 K under the N(2)gas flow and in the frequency range from 1 kHz to 1 MHz for ac electrical measurements. The dc conductivities and the activation energies were found to be in the range of 10(-13)-10(-12)S cm(-1)at the room temperature and 0.46-1.03 eV respectively. The increased C number in the alkyl chain and addition of metal ion to the porphyrin causes a decrease in the conductivity. The ac conductivity was well represented by the power law form A omega(s). The s parameter depending on temperature was varied 0.79-1.2. The conduction mechanism for all porphyrins could be related to small polaron tunneling (SPT) model. As an application, the NO(2)sensing properties of ZnPPC12 were investigated depending on temperature.