Crystallization-Induced Emission Enhancements of Hybrid Butenolide-Diphenylethenes.

Herein, we report crystallization-induced emission enhancement (CIEE) from five hybrid butenolide-diphenylethene derivatives. A combination of a flexible diphenylethene moiety with rigid butenolide core and specific electron-donating and withdrawing substituents led to favorable solid-state behavior in these simple molecules. Four derivatives (BuPh, BuOMe, BuCN, and BuBr) exhibited enhanced fluorescence in crystalline state (Φf ≤ 50%), while derivative BuCM showed dual-state emission (DSE) with excellent Φf of 90% in solution and good Φf of 22% in solid-state. Excitation-dependent emissions were also seen for derivative BuPh. These results identify the butenolide-diphenylethene framework as a compact and readily accessible scaffold for CIEE and DSE-active organic fluorophores.