Circularly Polarized Luminescence from Achiral Single Crystals of Hybrid Manganese Halides

[K(dibenzo-18-crown-6)] + ( KC ) cations are used for cocrystallization with manganese halides, producing isostructural single crystals of organic–inorganic hybrid complexes, [K(dibenzo-18-crown-6)] 2 MnX 4 (abbreviated (KC) 2 MnX 4 ) (X = Cl, Br), which feature one-dimensional morphology and green phosphorescence with considerable photoluminescence quantum yields accompanied by excellent optical waveguide behavior with a low loss coefficient. More interestingly, (KC) 2 MnX 4 crystallizes in the monoclinic space group Cc belonging to the achiral point group m ( C s ), where the non-centrosymmetric arrangement of racemic units, with right- and left-handed rotating optical axes, endows these achiral single crystals with circularly polarized luminescence, observed for the first time.