We designed a cross-linking polymerization system composed of inter- and intramolecular reactions on the basis of the model of the characteristic random coil morphology of macromolecules in solution. The cross-linking process in the system was controlled, and the soluble intramolecularly crosslinked macromolecule was successfully prepared in concentrated solution. It was found that this kind of macromolecule tends to form molecular clusters in solution by measuring molecular sizes and that the formation and dissociation of molecular clusters is in a nonequilibrium state, which could be a unique solution behavior of cross-linked macromolecules.