The application range for atomic layer deposition (ALD) has now been extended to include the deposition of rubidium-containing films, enabling the deposition of new and exploratory types of compounds by ALD. The properties of rubidium t-butoxide as an ALD precursor are promising, revealing similar behavior as its lithium, sodium and potassium counterparts. The deposition of rubidium containing films is reported as proof of concept through the Rb-Ti-O and Rb-Nb-O systems. Rubidium content in the doping level range of Rb is controllably achieved in Rb:TiOx up to 20%, whereas Rb can be introduced as a major component in Rb:NbOx. Perovskite RbNbO3, otherwise unattainable in bulk systems under ambient conditions, is shown to be stabilized on SrTiO3 (100) substrates. This report opens up the investigation of thin films of new and unexplored systems, not only in the world of ALD, but in materials chemistry in general.