It is shown that numerous complex polymer systems consisting of macromolecules, which exhibit not only distinct sizes but also chemical composition, can be comprehensively characterized by a novel simple and efficient method of sequenced two-dimensional liquid chromatography. In the first step, macromolecules are separated according to their chemical composition, irrespectively of their molar mass, with help of the unconventional method of liquid chromatography under limiting conditions of desorption. Thus-obtained fractions are in their entireties successively online forwarded into the size exclusion column for separation according to their molar mass. The effectuation of procedure is elucidated.