An electronic device containing a polythiophene prepared by a metal halide-mediated
coupling polymerization in an appropriate solvent, and which polythiophene is comprised
of at least one monomer unit selected from the group consisting of 2,5-thienylene
(or 2,5-thiophenediyl) (I), 2,5-thienylene (or 2,5-thiophenediyl) (II), and a divalent
linkage D
##STR1##
wherein, for example, A is alkyl, alkoxy or derivatives thereof; B is a
hydrogen atom, a small substituent like alkyl or alkoxy.
