A mesoscopic view of active droplets of an alkane on a Au(1 1 1) electrode was described using the results of voltammetric and in situ electrochemical fluorescence imaging measurements. In situ fluorescence imaging studies revealed that the morphology of an adlayer of liquid n-hexadecane (HD) on a Au(1 1 1) electrode surface is reversibly driven by potential, forming micro-droplets with greater height of the droplet's top at more negative potentials. Spreading of HD to be a continuous liquid film never took place even around pzc and even with the amounts of HD ranging from 10 to 10,000 monolayer equivalent. The droplets at negative potentials were smaller than 50 pm in diameter. The total Au electrode area occupied by HD was small even at positive potentials so that quasi-reversible redox reaction of ferri/ferro-cyanide in the solution phase was still observed. The change of the droplet height by the reshaping with the electrode potential was repeatable, and the change took place beyond the double layer thickness region. (C) 2016 Elsevier B.V. All rights reserved.