Aggregation-induced emission (AIE) is a unique photophysical phenomenon where AIE-active molecules are non-emissive or weakly emissive in the discrete state because of active intramolecular motions, but show enhanced luminescence upon aggregation due to mechanisms including the restriction of intramolecular motions (RIM), restricted access to a conical intersection, and restriction of access to the dark state. Various AIE luminogens (AIEgens) have been developed and have shown great potential for biomedical applications. In NIR-II bioimaging, the AIE strategy is also promising. Many NIR-II AIEgens with acceptable QYs can act as superior imaging materials (the highest QY approaches 15% using IR26 as the reference fluorophore with a QY of 0.5% in 1,2-dichloroethane). For instance, our group reported TPA-BBT in 2019, the nanoparticle of which demonstrated a very high QY of about 11% in water. However, the typical D-A-D structure of TPA-BBT caused a strong TICT effect and would suppress its QY in the aqueous solution. Hence, there is still a large room to further raise the QYs of NIR-II AIEgens by optimizing their molecular structures.