Electrochemical conversion of lignin for the production of high-value heterocyclic aromatic compounds has great potential. We demonstrate the targeted synthesis and cation modulation of NiCo2O4 spinel nanoboxes, synthesized via cation exchange and calcination oxidation. These catalysts exhibit excellent efficacy in the electrocatalytic conversion of lignin model compounds, specifically 2-phenoxy-1-phenylethanol, into nitrogen-containing aromatics, achieving high conversion rates and selectivities. These catalysts were synthesized via a cation exchange and calcination oxidation process, using Prussian blue nanocubes as precursors. The porous architecture and polymetallic composition of the NiCo2O4 spinel demonstrated superior performance in electrocatalytic oxidative coupling, achieving a 99.2 wt% conversion rate of the 2-phenoxy-1-phenylethanol with selectivities of 37.5 wt% for quinoline derivatives and 31.5 wt% for phenol. Key innovations include the development of a sustainable one-pot synthesis method for quinoline derivatives, the elucidation of a multistage reaction pathway involving C–O bond cleavage, hydroxyaldol condensation, and C–N bond formation, and a deeper mechanistic understanding derived from DFT simulations. This work establishes a new strategy for lignin valorization, offering a sustainable route to produce high-value nitrogen-containing aromatics from renewable biomass under mild conditions, without the need for additional reagents.