The covalent linkage of supramolecular monomers provides a powerful strategy for constructing dynamic polymeric materials whose properties can be readily tuned either by the selection of monomers or the choice of functional linkers. In this strategy, the stabilities of the supramolecular monomers and the reactions used to link the monomers are crucial because such monomers are normally dynamic and can disassemble during the linking process, leading to mixture of products. Therefore, although noncovalent interactions have been widely introduced into metallacycle structures to prepare metallosupramolecular polymers, metallacyclecored polymers linked by covalent bonds have been rarely reported. Herein, we used the mild, highly efficient amidation reaction between alkylamine and N-hydroxysuccinimide-activated carboxylic acid to link the pendent amino functional groups of a rhomboidal metallacycle 10 to give metallacycle-cored polymers P1 and P2, which further yielded nanoparticles at low concentration and transformed into network structures as the concentration increased. Moreover, these polymers exhibited enhanced emission and showed better quantum yields than metallacycle 10 in methanol and methanol/water (1/9, vol/vol) due to the aggregationinduced emission properties of a tetraphenylethene-based pyridyl donor, which serves as a precursor for metallacycle 10. The fluorescence properties of these polymers were further used in cell imaging, and they showed a significant enrichment in lung cells after i.v. injection. Considering the anticancer activity of rhomboidal Pt(II) metallacycles, this type of fluorescent metallacycle-cored polymers can have potential applications toward lung cancer treatment.fluorescent polymers | supramolecular coordination complex | covalent linkage | aggregation-induced emission | cell imaging F luorescent polymers have received much attention in the chemical and life sciences due to their promising applications in biological labeling, tracking, monitoring, imaging, and diagnostics (1-3). Compared with other fluorophores such as small molecules and quantum dots, they are advantageous as biomaterials because of their good biocompatibility, ease of preparation, and biomimetic character (4-6). Conventional fluorophores show good emission in dilute solution but experience varying degrees of aggregation-caused quenching due to the intense intermolecular interactions, which will decay or relax the excited state back to the ground state via nonradiative channels (7). Such fluorophores are not ideal candidates for the preparation of fluorescent polymers, because they need to be aggregated by the polymerization process, which will more or less decrease the fluorescence emissions and the quantum yields of the derived fluorescent polymers.In 2001, Tang and coworkers (8) reported an opposite fluorescence effect named as aggregation-induced emission (AIE). In such cases, fluorophores are nearly nonemissive as discrete molecules, but they exhibit strong fluorescence in concentrated solution or in the s...