The investigation of concentration effects in the solutions of luminescent compounds allows us to obtain the detailed information concerning interactions between molecules of dissolved substance. The increasing concentration of dye and pigment solutions is known to lead to the concentration depolarization phenomena (CDF) and the concentration quenching of fluorescence (CQF). At present the overall of these phenomena is rather widely investigated both in theoretical and experimental aspects. Nevertheless the problem of the mutual relation of the concentration depolarization and the concentration fluorescence quenching remains yet unsolved. The improvment of the CDF theory, undertaken in last years, as well the using new methods of investigation, give the real possibility to carry out the comparison of theory and experiment more strictly.