Abstract: The aggregation of molecules plays an important role in determining their functions. Electron microscopy and other methods can only characterize the variation of microstructure, but are not capable of monitoring conformational changes. These techniques are also complicated, expensive and time-consuming. Here, Prof. Tang and Prof. Qin's group demonstrate a simple method to monitor in-situ and in real-time conformational change of (R)-1, 1'-binaphthyl-based polymers during the aggregation process using circular dichroism. Based on the results from molecular dynamics simulations and experimental circular dichroism measurements, polymers with "open" binaphthyl rings show stronger aggregation-annihilated circular dichroism effects, with more negative torsion angles between the two naphthalene rings. In contrast, the polymers with "locked" rings show a more restrained aggregation-annihilated circular dichroism effect, with only a slight change of torsion angle. Prof. Tang and Prof. Qin's work provides an approach to monitor molecular aggregation in a simple, accurate, and efficient way, which is expected to be applied in the areas of life and health.