PURPOSE: To prepare the title composition of high conductivity and stability, and good film-forming and adhesive properties, by dispersing a specific quinodimethane complex salt in a polymer having functional groups and making a three-dimentional structure using a polyfunctional crosslinking agent.

CONSTITUTION: A functional group-contg polymer, a 7, 7, 8, 8- tetracyano-quinodimethane complex salt, and a polyfunctional crosslinking agent are dissolved together in a solvent such as N, N - dimethyl formamide, etc. The resulting solution is coated on, or impregnated with a base, followed by drying to make a three-dimentional structure, thus obtaining the objective composition suitable as an electrolyte material for solid electrolytic capacitors.