This invention relates to improved methods for the preparation, purification, and processing of poly(heteroaromatic) block copolymers, as well as compositions prepared by these methods. Methods relate to preparation of multiblock and triblock copolymers of intrinsically conducting polymers (ICPs) containing at least one block of a poly(heteroaromatic) polymer and at least two blocks of a non-conducting polymer. This invention provides polymer solutions or dispersions of improved stability and better film-forming properties. The poly(heteroaromatic) block copolymers are obtained in their conducting or doped form, and are retained in a solvated, wet form throughout the production and purification processes. Stable solutions or dispersions of the purified copolymers in organic solvents, water, or mixtures thereof are provided. Stable solutions or dispersions of ICPs are useful in the preparation of semiconducting and conducting films, blends, and coatings on a variety of substrates using standard processing and coating techniques.