The dependence of electronic states on the length and diameter of CdSe quantum rods is investigated usingsemiempirical pseudopotential calculations. Energy levels cross as the aspect ratio increases due to theirdifferent dependence on length. The crossover between the highest occupied levels leads to a transition fromplane-polarized to linearly polarized light emission at aspect ratio ca. 1.3. Further increasing aspect ratioresults in levels with similar symmetry converging and forming “bands”. This calculation demonstrates thetransition of electronic structure from zero-dimensional quantum dots to one-dimensional quantum wires.