In this work, we focus on non-branching alkanoate ligands which are the most commonly used ligands for semiconductor NCs. The current analyses are based on the system of spheroidal CdSe NCs with a core diameter of ~ 3.0 nm. The NC-ligands complexes have been purified to ensure the complete removal of free ligands and unreacted precursors (see Figure ). Using elemental analysis, we show that each CdSe NC is capped by ~ 150 carboxylate ligands (Table ). These ligands have variable number of carbon units (n = 6 to 22) and are named as C6 to C22, respectively. The ligands on NCs can be prepared as pure species (i.e., ligands of the same length) or as a binary mixture (i.e., ligands of unequal lengths). The mixed-ligand NCs are prepared by the ligand exchange process as described in the Supporting Information. The relative ratio of two ligands can be precisely measured and controlled.