NOVELTY - A method for the production of dispersions or solutions of optionally substituted polythiophenes (PT) in organic solvents involves (a) adding water-miscible organic solvent(s) to an aqueous dispersion or solution of (PT) and (b) removing at least some of the water.    USE - For providing substrates with a conductive finish, for the antistatic treatment of substrates (especially photographic materials), for the production of solid electrolytes in solid capacitors and for the production of electroluminescent systems. Applications include rechargeable batteries, LED's, sensors, cathode ray tubes, optical signal conversion, solar energy conversion and transparent electrodes (e.g. in touch screens).    ADVANTAGE - Combines the excellent conductivity and coating properties of dematerialized aqueous dispersions of ionic polythiophene complexes with the highly variable wetting and drying properties of organic solvents, thus facilitating, e.g. the production of conductive coatings on a wide range of substrates.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (i) a method as described above in which (PT) comprise ionic complexes of formula Polythiophene+ An-, in which    Polythiophene+ = polymers containing positively charged units of formula (I) or (II);    Y = -(CH2)m-CR1R2-(CH2)n- or optionally substituted 3-8C 1,2-cycloalkylene;    R1, R2 = H, hydroxymethyl, or optionally substituted 1-20C alkyl or 6-14C aryl;    m, n = 0-3;    Z = -(CH2)m-CR3R4-(CH2)n-;    R3 = H or -(CH2)s-O-(CH2)p-SO3- M+;    R4 = as for R3 (but not H);    s = 0-10;    p = 1-18;    M = a cation;    An = the anion of an organic polyacid    (ii) dispersions or solutions of (PT) in organic solvents containing little or no water;    (iii) methods for providing substrates with a conductive finish, for the antistatic treatment of substrates (especially photographic material), for the production of solid electrolytes in solid capacitors and for the production of electroluminescent systems by using these dispersions or solutions of (PT).