Disclosed is a polymeric composite material in which metal sulfide microparticles having optical characteristics are uniformly dispersed and suspended in a high polymer material at high concentration. The polymeric composite material comprises metal sulfide microparticles formed by a reaction of a functional group in a matrix forming material having the functional group, the metal sulfide microparticles being dispersed in a matrix. It is desirable that the matrix includes a compound having the structure represented by formulae (1) to (5). ##STR1##