Sensitizers) The crystal structure of trans-1,2-bis[2'-(5'-phenyloxazolyl)]ethylene laser dye was determine by x-ray diffraction. The crystal was monoclinic and the space group was P 21/c with a = 0.8268(2), b = 0.5977(2), c = 1.6292(3), b = 100.55(2)? V = 0.7915 nm3, Z = 2, and Dx = 1.319 g/cm3. The mol. was centrosym.; the 2 benzene and 2 oxazole rings were coplanar and twisted slightly to form a propeller-shaped mol. There was appreciable conjugation between the vinyl and oxazole rings as well as the oxazole and benzene rings.

Key words: X-RAY DIFFRACTION ANALYSIS, CRYSTAL STRUCTURE DETERMINATION, ETHYLENE P, CONFIGURATION