We have examined the complex formed by clay minerals and porphyrins. The molecular orientation of cationic porphyrin on the clay surface was investigated in the present study. It was found that four cationic porphyrin adsorbs on the clay surface with parallel orientation. In case of two cationic porphyrin, the orientation angle of porphyrin molecule to the clay surface was found to be affected by the composition of bulk solvent.
