The synthesis and crystal structure of bis(o-phenylenethiourea)selenium(II)-chloride dihydrate, Se(C7H6N2S)2Cl2·2H2O are reported. The compound crystallizes in the monoclinic space group, P21/n, with four molecules per unit cell, the dimensions of which are a=10.243(3), b=13.341(4), c=14.273(4) Å, β=93.00(3)°, U=1947.76 Å3. The structure was solved by direct methods and refined by full-matrix least-squares to R=0.039 and Rw=0.040 for 3314 unique reflections. Selenium displays two strong coordinations arising from the two sulfurs, Se-S(1)=2.191(1), Se-S(2)=2.206(1) Å, and S(1)-Se-S(2)=101.0(1)°, and four secondary interactions involving three chlorines and one sulfur. The complex occurs as a dimer with two sets of very weakly interacting bridging pairs S(2), S(2)a; and Cl(2), Cl(2)a, where "a" denotes the inversion related atom. Lattice stabilization is ensured by the extensive network of hydrogen bonds involving chlorines, water oxygens, and nitrogens of phenylenethiourea ligands. © 1989 Plenum Publishing Corporation.