Complex polymers are distributed in more than one direction of molecular heterogeneity.In addition to the molar mass distribution, they are frequently distributed with respect to chemical composition,functionality, and molecular architecture.For the characterization of the different types of molecular heterogeneity it is necessary to use a wide range of analytical techniques.Preferably, these techniques should be selective towards a specific type of heterogeneity.The combination of two selective analytical techniques is assumed to yield two-dimensional information on the molecular heterogeneity.