1-Methyl-2-phenylindolizine-3-acetonitrile was unexpectedly obtained in the reaction of 1-methyl-2-phenylindolizine-3-thioaldehyde with cyanide ions. Its structure was determined by IR, H-1 NMR, MS, elemental analyses, and X-ray crystallography. Colorless regular prism shaped crystals of C17H14N2 crystallize in the space group C2/c with cell dimensions a = 12.956(3) Angstrom, b = 10.516(2) Angstrom, c = 20.429(4) Angstrom and alpha = 90degrees, beta = 104.98(3)degrees, gamma = 90degrees, V = 2688.7(9) Angstrom(3), D-calc = 1.217 Mg/m(3), and Z = 8.