A new method in which supramolecular polymerization is promoted and controlled through self-sorting is reported. The bifunctional monomer containing p-phenylene and naphthalene moieties was prepared. Supramolecular polymerization is promoted by selective recognition between the p-phenylene group and cucurbituril (CB), and 2:1 complexation of the naphthalene groups with cucurbituril (CB). The process can be controlled by tuning the CB content. This development will enrich the field of supramolecular polymers with important advances towards the realization of molecular-weight and structural control.