Polymer-analogous reactions represent deliberate changes of functional groups that are carried in macromolecular chains with the general objective of maintaining the polymerization degree of the original macromolecules. In comparison with low-molecular-mass analogs, the reactivity of the func-tional groups in macromolecules depends on the diffusional mobility of the reactants, intermediates, and products in the reaction mixture and steric hindrance to the approach of reagents to functional groups. A lower or enhanced reaction rate in polymer systems is a consequence of the primary, secondary, and tertiary structure of the polymer chains. For chemical modi-fication of macromolecules, different types of reactions can be used. From the structure of the basic unit of poly(2,6-dimethyl-1, Cphenylene oxide)(PPO)