Metal-free organic materials with multifarious luminescent properties have attracted considerable attention because of their promising applications in the fields of organic lightemitting diodes (OLEDs), sensors, biological imaging, and anti-counterfeiting. As we know, the bulk properties of organic materials used in the real world are not just governed by the properties of a single molecule but also by its packing modes. However, most conventional chromophores with planar configuration suffer from the notorious aggregation-caused quenching (ACQ) effect upon aggregation. Until 2001, Tang and co-workers firstly coined the concept of aggregation-induced emission (AIE), which is diametrically opposed to the ACQ effect. The AIE luminogens (AIEgens) are weakly or non-emissive as free molecules but show remarkably enhanced emission when aggregated. Owing to this unique advantage, AIEgens have been widely used in various high-tech applications in the past two decades. Recently, some exciting luminescent properties such as thermally activated delayed fluorescence (TADF), room-temperature phosphorescence (RTP), and mechanoluminescence (ML) have been successfully achieved in certain AIEgens. It should be noted that TADF and RTP are two pathways to harvest "dark" triplet states for potential applications in the optoelectronic and biological areas while stimuli-responsive ML is promising for smart sensing and switching devices. To obtain desirable emission properties and hence fulfill the requirements for versatile practical applications, enriching the diversity of excellent chromophores by molecule engineering is of significant importance. Over the past decades, various strategies such as changing the position of substituents , tailoring the length of alkyl chains , altering the central core, and introducing functional groups have been devised to modify the molecular structures, thus tuning the electronic structure or molecular packing motif to obtain diverse luminescent properties. Except for the intrinsic electronic structure, intermolecular interactions and molecular packings also play crucial roles in tailoring the luminescent behaviors of organic aggregates. Accordingly, in addition to chemical modifications, physical treatments such as light irradiation, heating, applying mechanical force, and changing solvent polarity have been widely used to realize dynamic emission behaviors So far, although organic materials with different emissive properties such as AIE, TADF, RTP, and ML have been developed well independently , how to rationally design and tailor the molecular structure within macroscopic aggregates to obtain desired emission properties remains a big challenge.