A meso-palladioporphyrin intermediate was isolated from a Heck reaction between an iodoporphyrin and a non-activated olefin using a Pd(PPh3)2Cl2/Et3N system; its structure was characterized by NMR, MS and X-ray crystallography. Studies on its formation indicate that the Pd(II) catalyst was reduced in situ by Et3N with the assistance of water. The catalytic activity of the intermediate was confirmed by stoichiometric and catalytic reactions using a more reactive olefin, ethyl acrylate.