A folded mechanochromic organic fluorophore based on thianthrene-fused coumarin

Abstract

The powder samples of a novel thianthrene-fused coumarin dye (6,7-BDTC) demonstrated pronounced mechanochromic luminescence, shifting from light-blue to green emission upon mechanical stimulation. X-ray crystallography of polymorphs with different emission colors revealed that this responsiveness originates from variations in the packing mode induced by the D–A type folded structure. These results demonstrate that introducing a folded π-conjugated framework into the coumarin core enables control over the packing mode and emission properties in the solid state.