We report a simple, single-pot, room temperature synthetic route to prepare colloidally-stable pyrogallol[4]arene-capped gold nanoparticles. The number of carbon atoms in the pyrogallol[4]arene pendent alkyl chain and the addition of base (e.g., NaOH) are both found to significantly impact the resulting colloid size, stability, and catalytic activity for nitroarene reduction.