A polymer compound having a functional group containing a cyclic part with aromatic properties comprising C, H and/or C, H, X (X is a hetero atom) in the side-chain, and a number average molecular weight of 250-1,000,000. The molar optical absorption due to the cyclic part with aromatic properties of the polymer compound is lower 30% or more than the molar optical absorption due to the cyclic part with aromatic properties in a polymerizing monomer used to introduce the cyclic part with aromatic properties. As this cyclic part has an overlapping stack structure, the compound has a hypochromic effect, and if an electron donor compound or electron-accepting compound is added, a charge transfer complex is formed.