Conductive polymer solution, conductive coating, capacitor and process for manufacturing capacitor

A conductive polymer solution, comprising a À-conjugated conductive polymer, a polyanion. a conductive improver (or a dopant), an alkaline compound and a solvent. The conductive improver is one or more compounds selected from the group of nitrogen containing aromatic cyclic compounds, compounds containing one or more hydroxyl group, compounds containing two or more carboxyl groups, compounds containing one or more hydroxyl or carboxyl groups, the compound containing an amide group, compounds containing an imide group, lactam compounds, and compounds containing a glycidyl group. Further, the alkaline compound is a nitrogen containing aromatic cyclic compound. A capacitor, comprising an anode (11) composed of a valve metal, a dielectric layer (12) formed by oxidation of a surface of said anode, and a solid electrolyte layer (13) formed on a surface of said dielectric layer, and a cathode layer (14) formed on the solid electrolytic layer is obtained.