Nickel (II) hydroxide nanoparticles with very high oxidative electrocatalytic activity toward sugars have been prepared on different electrodes by a simple electrochemical procedure consisting of the following: (i) electro-oxidation of a dinickel precursor that produces microstructures of a novel paddle–wheel tetrakis-acetato dinickel (II) complex and (ii) subsequent alkaline treatment of these microstructures to produce nickel (II) hydroxide nanoparticles on the electrode. The novel paddle–wheel complex has been characterized by energy-dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), and mass spectrometry. The proposed electrochemical mechanism for the surface generation of this complex involves coupling of homogeneous chemical reactions to heterogeneous electron-transfer reactions. The high and homogeneous coverage and the 1–3 nm size of the nickel hydroxide nanoparticles generated play key roles in the electrocatalytic efficiency and the reproducibility toward the oxidation of several sugars. The high sensitivity values obtained prove the utility of the method to develop nickel hydroxide-modified electrodes for sensing and electrocatalysis applications.