diphenyl ethylene

from The Collaborative International Dictionary of English v.0.48

Stilbene \Stil"bene\, n. [See {Stilbite}.] (Chem.)
   A hydrocarbon, {C14H12}, produced artificially in large, fine
   crystals; -- called also {diphenyl ethylene}, {toluylene},
   etc.
   [1913 Webster]