Multidimensional (nD) NMR spectroscopy has become a powerful and indispensable tool in elucidating the structures and dynamics of large macromolecules. This technique has routinely been used for microstructure analysis of copolymers for decades. A detailed knowledge of the structural features of a polymer is important to establish the structure-property relationship. But the complexity of polymer microstructure is increasing as more than two monomers are combined to make new materials for diversified as well as unique applications. Techniques like isotopic labeling, selective excitation, pulsed field gradient in combination with multidimensional NMR are being successfully used to solve challenges associated with large and complex biopolymers. Combination of these techniques, which are used in bio-NMR for long time, along with nD-NMR can also be used to analyze the structure of complex polymers and materials. In this book, application of new multidimensional NMR methods, which incorporate the above mentioned techniques, in microstructure analysis of complex polymers, has been discussed.