Neutron diffraction experiments and Korringa-Kohn-Rostoker with coherent potential approximation electronic band structure calculations as well as electrical resistivity measurements have been performed on polycrystalline Mo3-xRuxSb7 samples for 0 <= x <= 1. Neutron diffraction studies have been undertaken at room temperature and extended down to 4 K to get a better understanding of the crystalline structure modifications as the Ru content increases. Both structural and chemical characterizations have unambiguously revealed a solubility limit of the Ru atoms close to 0.8. Electronic band structure calculations have provided theoretical evidence of a progressive transition from a metalliclike state (x=0) toward a semiconducting-like character as x=1 is approached, although the solubility limit of Ru precludes a crossover to a semiconducting behavior. The theoretical prediction has been experimentally confirmed by low-temperature electrical resistivity measurements from 2 up to 350 K.