Two polymorphs emitting near-infrared (1 R form: α phase, λ_em=702 nm, Φ_f=0.41) and orange-red fluorescence (1 O form: β phase, λ_em=618 nm, Φ_f=0.05) were synthesized by finely controlling the crystallization conditions of compound 1, a structurally simple excited-state intramolecular proton transfer (ESIPT)-active molecule. Multicolor amplified spontaneous emissions (ASEs) were realized, for the first time, based on these polymorphs. Notably, the 1 O crystal underwent heating-induced phase transformation from the β phase to the α form in a single-crystal to single-crystal (SCSC) manner accompanied with an unprecedented ASE changing. The ASE behavior of polymorphs 1 R, 1 O as well as the ASE changing during SCSC was investigated. The feasibility of multicolor lasing based on the present organic polymorphs was confirmed, which may provide a new development strategy for organic laser science and technology.

A series of highly efficient deep red to near-infrared (NIR) emissive organic crystals 1–3 based on the structurally simple 2′-hydroxychalcone derivatives were synthesized through a simple one-step condensation reaction. Crystal 1 displays the highest quantum yield (Φ_f) of 0.32 among the reported organic single crystals with an emission maximum (λ_em) over 710 nm. Comparison between the bright emissive crystals 1–3 and the nearly nonluminous compounds 4–7 clearly gives evidence that a subtle structure modification can arouse great property changes, which is instructive in designing new high-efficiency organic luminescent materials. Notably, crystals 1–3 exhibit amplified spontaneous emissions (ASE) with extremely low thresholds. Thus, organic deep red to NIR emissive crystals with very high Φ_f have been obtained and are found to display the first example of NIR fluorescent crystal ASE.

A series of highly efficient deep red to near-infrared (NIR) emissive organic crystals 1–3 based on the structurally simple 2′-hydroxychalcone derivatives were synthesized through a simple one-step condensation reaction. Crystal 1 displays the highest quantum yield (Φ_f) of 0.32 among the reported organic single crystals with an emission maximum (λ_em) over 710 nm. Comparison between the bright emissive crystals 1–3 and the nearly nonluminous compounds 4–7 clearly gives evidence that a subtle structure modification can arouse great property changes, which is instructive in designing new high-efficiency organic luminescent materials. Notably, crystals 1–3 exhibit amplified spontaneous emissions (ASE) with extremely low thresholds. Thus, organic deep red to NIR emissive crystals with very high Φ_f have been obtained and are found to display the first example of NIR fluorescent crystal ASE.

In investigations into the effects of environmental factors on organogels, two urea-functionalized quinacridone derivatives 1 a and 1 b have been designed and synthesized. These two compounds can respond to ultrasound and thermal stimuli in the organic test solvents, and exhibit pronounced aggregation properties. The field-effect (FE)-SEM images of xerogels show the characteristic gelation morphologies of 3D fibrous network structures. The concentration- and temperature-dependent ¹H NMR spectra suggest that the intermolecular π–π and hydrogen-bonding interactions of gelators are the main driving forces for the supramolecular assembly process. X-ray diffraction (XRD), UV/Vis absorption, and photoluminescent spectroscopy studies have been carried out and provide more information to define the molecular packing model in gelation states.