Aggregate Science: from Molecules, beyond Molecules

Over the past centuries, molecular science has played a dominant role in the advancement of physical science by exploring the structure-property relationships at a single molecular level. However, when molecules form aggregates, a dilemma arises as the structures and properties often differ significantly from those of molecular constituents. To address this, the concept of aggregate science emphasizes a holistic approach to understanding the structures-properties relationship of substances. Despite the recognition of holism in aggregate research, there are still challenges in investigating the complex operations and interplays, particularly in understanding the newly emergent structures and properties in the macroscopic world. Therefore, there is a need to further advance the concept and methodology. In this regard, this perspective highlights three types of influences that aggregation exerts on substance properties: activation, transformation, and emergence. Furthermore, examples from aggregation-induced emission research and related fields are provided to illustrate how aggregate science can be studied. This perspective emphasizes that the molecule is of significance and the structures and properties are also dramatically influenced by aggregation. Additionally, potential research methodologies, such as focusing on intra- and intermolecular interactions, adjusting aggregates morphology, and regulating the constituents, along with directions, and implications are offered for future studies.