(Z)-1-(2-Bromo-1,2-diphenylethenyl)-4-ethylbenzene, C22H19Br, Mr = 363.3, triclinic, P1, a = 8.0838 (8), b = 9.4510 (8), c = 11.565 (1) A, alpha = 91.464 (8), beta = 89.563 (9), gamma = 90.828 (8) degrees, V = 883.2 (2) A3, Z = 2, Dx = 1.366 Mg m-3, lambda(Cu K alpha) = 1.5418 A, mu = 3.13 mm-1, F(000) = 372, T = 294 (1) K, R = 0.031 for 2764 independent reflections. All the bond distances and angles are normal. To avoid steric hindrance, the three phenyl rings are twisted out of the plane calculated for the two atoms involved in the ethylenic bond and the four atoms linked to them. The dihedral angles of their least-squares planes with that of the ethylene group are in the range 47.77 (7)-57.86 (7) degrees. The cohesion of the structure is due to van der Waals interactions. A mixture of the (Z)- and (E)-isomers (Broparestrol, INN) is used in dermatology. The (Z)-isomer exhibits some aspects of the antiestrogenic activity and other actions that may be connected to the estrogenic properties. Therefore information on the (Z)-isomer geometry was required to understand the structure-activity relationship.