Au₁₃₇(SR)₅₆, a nanomolecule with a precise number of metal atoms and ligands, was synthesized. The composition was confirmed by MALDI and ESI mass spectrometry using three unique ligands (–SCH₂CH₂Ph, –SC₆H₁₃, and –SC₄H₉) and nano-alloys with Ag and Pd. The electrocatalytic properties were tested for CO₂ reduction.