We prepared three types of poly(thiophene)s having aminoalkyl substituents: poly(3-aminoethylthiophene), poly(3-aminododecylthiophene), and poly [2,5-(3-octadecylthiophene)-alt-2,5-(3-aminomethlthiophene)]. From the absorption spectra of the poly(thiophene) films, it was demonstrated that their mean pi-conjugation length was shortened compared to poly(3-alkylthiophene) prepared by the same chemical way. When a spin-coated film of hydrogen bromide salt of poly(3-aminododecylthiophene) was soaked in aqueous solution of PbBr2, PbBr-based layered perovskite structure combined with a semiconductor layer of two-dimensional sheets of PbBr6 octahedra and an organic semiconductor layer of poly(thiophene) was formed; sharp exciton absorption of approximately 400 nm, which is the characteristic of PbBr-based layered perovskite was observed. (C) 2003 Elsevier Science B.V. All rights reserved.