Tunable mechanochromic luminescence of 2-alkyl-4-(pyren-1-yl)thiophenes: controlling the self-recovering properties and the range of chromism.

Controlling the behavior of mechanochromic luminescence (MCL) based on rational design principles is an outstanding challenge. Herein, an unprecedented self-recovering MCL that manifests in a large shift of the emission maximum (∼200 nm) has been achieved for 2-alkyl-4-(pyren-1-yl)thiophenes upon introducing long alkyl chains and mixing with N,N'-dimethylquinacridone.