The 1 : 2 molar reactions of MoCl5, in dichloromethane at room temperature, with tetrahydrofuran (thf), tetrahydropyran (thp), dioxane and tetrahydrothiophene (tht) afforded, respectively, [Mo(O)Cl-3(thf)](2), 1, and MoCl4(L)(2) (L = thp, 2; dioxane, 3; tht, 4), in 81-87% yields. The molecular structures of 1, 2 and 4 were ascertained by X-ray diffractometry. DFT and spectroscopic (IR, NMR) studies were carried out in order to shed light on thermodynamic and kinetic aspects of the reaction pathways.