The solution phase synthesis of narrow diameter CdSe and PbSe nanowires (NWs) is described. Crystalline NWs with lengths between 1–10 μm are obtained using a seeded solution approach, whereby NW growth is catalyzed by Au/Bi core/shell nanoparticles (NPs). A gold biphasic reduction step results in 1.5 (3) nm diameter Au NPs and is followed by the thermolysis of trialkylbismuthines to yield low melting, bimetallic particles with diameters less than 3 nm. These Au/Bi NPs are catalytically active towards the growth of similar diameter CdSe NWs (∼7 nm) that exhibit quantum confinement effects. By varying the ratio of Cd (or Pb) to Se, both straight and branched NWs can be obtained, with branched structures including v-shapes, tripods, and y-shapes in the case of CdSe and t-shapes in the case of PbSe. Structural characterization shows that both straight and branched CdSe NWs grow along either the <111> zinc blende (ZB) or <0001> wurtzite (W) directions. Conversely, PbSe has a rocksalt crystal structure, and both straight and branched NWs grow along <100> directions.