[d] Instead of water/SDS. [e] 24 h. i.r. isomeric ratio By examining the photophysical mechanism of the reaction by exciting a solution of 1a under optimized conditions, i.e., excitation wavelength (λexc) of 456 nm and concentration of 35 mM in 4wt% SDS/water, we observed a broad emission band in the near-infrared (NIR) region with maximum around 700 nm (Figure ). Noteworthy, this emission is not occurring under different experimental conditions. Indeed, the band was not appearing by using lower concentrations of 1a (Figure , S3), as well as by exciting in the UV-region (e.g. 310 nm, Figure ) regardless of the concentration. The absence of the NIR band was also confirmed in organic solvents like DCM or MeOH, where the emission occurs in the visible region (Figure ). These circumstances suggest that the emission is strictly connected with the dense packing conditions obtained only in the micellar environment. It is important to emphasize that the photophysical studies on the investigated chalcone 1a have been already reported in literature, but radiative transitions generating emission bands in the NIR region have not been previously observed. The excitation spectrum of the band at 700 nm recorded under the synthetic conditions (Figure ) shows that the emission can be stimulated by exciting in the range between 400 and 470 nm, which fits perfectly with the emission spectrum of the 456 nm lamp used for the reaction. At the same time, the excitation spectrum justifies the lack of NIR band by exciting in the UV region. To get further insights on the origin of the unexpected emission band, lifetime experiments were carried out. Figure reports the recorded radiative decay with an average lifetime of 19.22 µs, indicating the phosphorescence as radiative mechanism, thus involving a triplet state. Literature data show that chalcones exhibit a triplet-state biradical with twisted structure with long triplet state lifetimes (up to 500 ns) depending on the substitution, but there are no reports of radiative decays in the microseconds scale. Noteworthy, the longest lifetime is associated with an increasing planarity of the biradical, which results in an increasing energy gap between triplet and ground states that are normally quasidegenerate. The unsubstituted chalcone investigated in our work should exhibit triplet state with lifetime of 12 ns. As consequence, we suppose that the spatial confinement in the micellar environment induces either strong planarity to the single biradical species, or formation of planar aggregates with AIE character. This hypothesis supports the idea that we have monomers and the second species with multiple molecules, an aggregate (I). The weakness and broadness of the NIR band can be explained by the high flexibility of aldehydes and ketones in the excited state. To assess the proposed aggregation state, a large amount of 1a was dissolved in THF and injected in water under sonication, inducing the formation of aggregate. The observed emission is equal to the emission in micellar media (Figure ) supporting the hypothesis of aggregates. It is important to emphasize that the NIR emission is not occurring in organic solvents by simply increasing the concentration, and the unique microenvironment of micelles is critical to reach the planarity and to enlarge the energy gap S0-T1. Advanced systems sometimes utilize encapsulation in micelles to improve fluorescence quantum yield and fluorescence lifetime of organic dyes. Nevertheless, this discovery was unexpected, as the system under investigation lacks the typical characteristics of advanced systems for room-temperature phosphorescence (RTP). The micellar system induces AIE from an inexpensive and commercially available non-specialized molecule in water. Our results contribute to recent developments in photocatalysis devoted to move away from transition metal-based dyes towards purely organic dyes and limit the use of toxic solvents. We therefore propose that the [2+2] photocycloaddition in our case proceeds via a micelle mediated triplet state aggregate with an average lifetime of 19.22 µs (Scheme 1). The excited state lifetime is uniquely long for a non-designed purely organic molecule, which may be key for the productive triplet state reaction reactivity.