Necklace-like nanostructures with SiOx beads on boron strings are self-assembled via a facile environment-friendly method at atmospheric pressure. The electrical conductivity of the boron string is a thousand times higher than that of bulk boron. Due to the unique mechanical interlocking between beads and epoxy matrix, the reinforcement effect of the nanonecklaces in epoxy is better than normal carbon nanotubes. B/SiOx nanonecklaces are expected to exhibit unique electrical and mechanical properties for constructing nanodevices