Vapor-deposited molybdenum oxide films are used as low resistance anode interfacial layers in applications such as organic light emitting diodes (OLEDs) and organic photovoltaics (OPVs). A versatile method for the vapor deposition of molybdenum oxide layers is presented, which offers the control of the oxygen stoichiometry of the deposited films and their doping with hydrogen. The possibility of tuning the electronic structure of the deposited molybdenum oxides is also investigated by controlling oxygen deficiency and hydrogenation (the incorporation of hydrogen within the molybdenum oxide's lattice). To take advantage of the altered electronic properties of the non-stoichiometric Mo oxides, we embedded them as anode interfacial layers in organic optoelectronic devices. Large improvement in the operational characteristics of both electroluminescent devices and bulk heterojunction solar cells was achieved and correlated with the oxygen deficiency and the hydrogen content of the Mo oxides.