4-Bromostyrene is a para-halogenated styrene derivative. The proton spectra of 4-bromostyrene exhibits dipolar couplings consistent with planar ground state structures, only if the torsional motion of lowest frequency occurs at about 80cm-1. It undergoes Heck reaction with 2-bromo-6-methoxynaphthalene in the presence of sodium acetate and Hermann′s catalyst in N,N-dimethylacetamide to afford diarylethene.