efficient and facile methodology for the regioselective nitration of two series of thien-2-ylporphyrins, 5,10,15,20-tetrakis(thien-2-yl)porphyrinato nickel(II) and 5,10,15,20-tetrakis(5-methylthien-2-yl)porphyrinato nickel(II) is presented. X-ray crystal structures of a few of the synthesized compounds are given. The effect of relative orientation of meso thien-2-yl rings with the porphyrin central π-system