Semiempirical molecular orbital calculations at the level of AM1-RHF were carried out on octahalotetraphenylporphyrins having Zn as the central ion. All the structures considered were found to be stable but endothermic. They all possess the dipole moment which is smallest for the octafluoro but highest for the octaiodo derivative. The polarizabilities follow the same trend. Calculations suggest that these systems should have anisotropic polarizabilities and thus some nonlinear properties should exist. (C) 2001 Elsevier Science B.V. All rights reserved.