The X-ray powder diffraction pattern for a new precursor in the synthesis of pyridyl tetrahydroquinolines was determined. 4-N-(4-methylphenyl)amine-4-(3′-pyridyl)-1-butene is monoclinic with refined unit cell parameters a=16.554(5), b=7.204(2), c=12.257(3) Å, β=99.76(2)°, V=1440.5(4) Å3, Z=4, and Dx=1.098 g/cm3, with space group P21/n (No. 14).