Although some bright, organic mechanoluminescence (ML) luminogens with aggregation‐induced emission properties and twisted molecular structures are recently reported, those with planar structures and bright ML and their related effective design strategies are not yet explored, partially due to aggregation‐caused quenching in luminogens with planar structures. Herein, using the unique solid‐state packing style of pyrene, bright dual monomer‐excimer‐ML and excimer‐ML from two pyrene derivatives (Py‐Bpin and Py‐Br) with a simple, planar molecular structure are reported for the first time, and two analogs of pyrene and Py‐H are used for comparison. These four luminogens display similar optical properties in dilute solution but different luminescent properties in the solid state, mainly due to their different molecular packing. Interestingly, pyrene is mechanochromism (MC)‐ and ML‐inactive, while Py‐H is MC‐active, Py‐Bpin is MC‐ and ML‐active, and Py‐Br is ML‐active. The relationship between molecular packing and ML/MC properties is confirmed by analyzing single‐crystal structures and related experimental results, providing important information to further understand the mysterious ML process and opening a new way to design efficient luminogens with both MC and ML.

Development of high‐performance dopant‐free hole‐transporting materials (HTMs) with comprehensive passivation effects is highly desirable for all‐inorganic perovskite solar cells (PVSCs). Squaraines (SQs) could be a candidate for dopant‐free HTMs as they are natural passivators for perovskites. One major limitation of SQs is their relatively low hole mobility. Herein we demonstrate that polymerizing SQs into pseudo two dimensional (2D) p–π conjugated polymers could overcome this problem. By rationally using N,N‐diarylanilinosquaraines as the comonomers, the resulting polysquaraine HTMs not only exhibit suitable energy levels and efficient passivation effects, but also achieve very high hole mobility close to 0.01 cm−2 V−1 s−1. Thus as dopant‐free HTMs for α‐CsPbI2Br‐based all‐inorganic PVSCs, the best PCE reached is 15.5 %, outperforming those of the doped‐Spiro‐OMeTAD (14.4 %) based control devices and among the best for all‐inorganic PVSCs.

Organic room temperature phosphorescence (RTP) materials with ultralong lifetime possess the remarkable advantage in bioimaging for elimination of background noise by characteristic time scale. However, most of RTP luminogens need to be excited by the harmful ultraviolet (UV) lamp, and exhibit green or yellow emission with shallow tissue penetration, constraining the in vivo bioimaging for further application in clinical diagnosis and pathological study. In this text, the much safer excitation process by sunlight and mobile phone flashlight is realized by organic luminogens with various electronic pull–push systems. Moreover, the bright red RTP emission with lifetime up to 344 ms is achieved by optimizing molecular geometry and electronic property. Especially, the mobile phone flashlight‐excited red afterglow imaging of lymph nodes in living mice has been realized for the first time, affording a safe and conventional approach to achieve the afterglow imaging of living mice with deep issue penetration and high signal‐to‐noise ratios.

Mechanoluminescence (ML) and room‐temperature photophosphorescence (RTP) were achieved in polymorphisms of a triphenylamine derivative with ortho‐substitution. This molecular packing‐dependent emission afforded crucial information to deeply understand the intrinsic mechanism of different emission forms and the possible packing–function relationship. With the incorporation of solid‐state 13C NMR spectra of single crystals, as well as the analysis of crystal structures, the preferred packing modes for ML and/or RTP were investigated in detail, which can guide the reasonable design of organic molecules with special light‐emission properties.

The development of fluorogens with deep-red emission is one of the hottest topics of investigation in the field of bio/chemosensors and bioimaging. Herein, the tunable fluorescence of perylene diimide (PDI) derivatives was achieved by the incorporation of varied isolation groups linked on the PDI core. With the enlarged sizes of isolation groups, the conversion from aggregation caused quenching to aggregation-induced emission was obtained in their fluorescence variations from solutions to nanoparticles, as the result of the efficient inhibition of π-π stacking by the larger isolation groups. Accordingly, DCzPDI bearing 1,3-di(9H-carbazol-9-yl)benzene as the biggest isolation group exhibited the bright deep-red emission in the aggregated state with a quantum yield of 12.3%. Combined with the three-photon excited fluorescence microscopy (3PFM) technology, through-skull 3PFM imaging of mouse cerebral vasculature can be realized by DCzPDI nanoparticles with good biocompatibility, and the penetration depth can be as deep as 450 μm.