In the title compound, C23H32N4Se, was synthesized and its crystal structure was determined by single crystal X-ray diffraction. The compound crystallizes in orthorhombic system, space group Pbca, a = 10.9960(10)Angstrom, b = 14.9460(9)Angstrom, c = 27.565(5)Angstrom and Z = 2. According to X-ray crystallographic studies, the diazepine ring is observed to be in a disordered state. The site-occupancy of the major compenent refined to 0.53(1). The C=Se bond length of 1.862(4)Angstrom is a double bond character. The dihedral angle between the two phenyl rings is 37.7(2)degrees.