1,4,7,10-Tetrathia (12-crown-4)-bridged new polymeric phthalocyanines 9 and 10 have been synthesized by the reaction of tetracyanodibenzo[1,4,7,10-tetrathia (12-crown-4)] in the presence of a strong organic base or Zn(OAc)(2) respectively. Furthermore, 1,4,7,10-tetrathia (12-crown-4)-linked peripherally octa-substituted dimeric phthalocyanine 12, which contains a combination of hexakis(alkylthia) side chains was synthesized by the reaction of subphthalocyanine 11 with the iminoisoindoline derivative 8. The new compounds have been characterized by elemental analyses, IR, UV/vis, mass, H-1 NMR and C-13 NMR spectroscopy. The thermal stabilities of the compounds were determined by thermogravimetric analysis. The electrical conductivity of the polymeric, 9 and 10, and dimeric phthalocyanines, 12 and 13, are in the semiconductor range; chemical doping with NOBF4 increases the d.c. conductivity of 10 by a factor of four. (C) 1997 by John Wiley & Sons, Ltd.