Organic molecular aggregates have attracted widespread attention over the past decade owing to their unique optoelectronic properties in the aggregate state, which mainly involves the effects of aggregation structure as well as molecular packing mode. Although many examples of H‐ and J‐aggregates defined by molecular exciton model have been found, there are also other types of unconventional aggregates, especially for aggregation‐induced emission (AIE) system. In this review, the recent progress of some examples of basic and novel aggregate forms, as well as coassembled forms, presenting distinctive optical features, such as optical waveguide and polarization emission, polymorph‐dependent emission and stimuli‐responsive luminescence are presented. The systematic insight into the relationship between the aggregation structure and emission property is discussed. Guidelines are therefore anticipated and will direct the future preprogramming molecular design so as to fine‐tune the emission feature through a specific aggregation model for developing organic molecular aggregates with desirable optoelectronic properties.

The latest advances in the development of fluorescent nanoparticles (FNPs) based on AIE fluorogens for bioimaging were summarized.

A novel divinylanthracene derivative 9,10-bis((E)-2-(pyridin-4-yl)vinyl)anthracene (BP4VA) was synthesized and its two polymorphs with different crystal structures were obtained. The introduction of pyridine in BP4VA leads to multi-stimuli responsive fluorescence. An investigation of the photophysical and stimuli responsive luminescent properties of BP4VA, including the piezochromism and protonation effect, demonstrates that the piezochromic luminescence originates from changes in the molecular aggregation state. Additionally, protonation–deprotonation of the pyridine moieties in BP4VA has a significant effect on the frontier molecular orbitals, resulting in distinct green and red emissions under acid and base stimuli. This study on BP4VA provides a comprehensive insight into the mechanisms within this type of stimuli-responsive luminescent material, and suggests that BP4VA may be a potential candidate for applications in sensing, detection and display devices with remarkable color-changing properties.