The implementation of renewable electricity generation, like wind and solar, is hindered by their strong dependence on weather conditions, which renders these energy sources unreliable for on-demand electricity grid supply. To address the intermittency of renewable energy sources, aqueous rechargeable zinc-ion batteries (ZIBs) offer attractive advantages such as safety, low cost, and recyclability. Currently, ZIBs face important technological challenges, particularly related to energy density and operational durability of the cathode materials conventionally used. Organic molecules offer advantages over metal-oxide based cathodes such as MnO2 due to the flexibility in molecular structure design to tailor redox properties and stability. Additionally, organic materials can be synthesized as opposed to relying on extraction (mining) of raw mineral inputs, which can damage the environment. However, organic cathodes experience important drawbacks that primarily affect their capacity stability, like dissolution during battery cycling, and inactivating side reactions. In this work, we aim to enhance the discharge capacity and capacity retention of an organic cathode material with anhydride groups (parent molecule) through the chemical modification of its structure employing a scalable process. The product obtained (synthesized material) incorporates additional organic sites for energy storage and substitutes the anhydride groups for imide groups. Cyclic voltammetry of the synthesized material showed improved electrochemical stability compared to the parent molecule, which exhibited constant shifts in the number of redox peaks and peak voltage. In the galvanostatic cycling, the synthesized material delivered higher discharge capacity at the initial discharge, compared to its parent molecule. Additionally, the capacity retention over 200 cycles at 100 mA/g was 26% higher for the synthesized material compared to the parent molecule, reducing the capacity fade rate by 2.71 mAh/g per cycle. Using Fourier transform infrared spectroscopy it was possible to observe changes in the functional groups of the synthesized material at pristine state, after the first discharge and after the first charge. The possible degradation mechanisms were investigated through rotating ring disk electrode, X-ray diffraction spectroscopy, and solid-state 13C nuclear magnetic resonance. No dissolution of the synthesized material was observed as a result of battery cycling. However, changes in the crystal structure of the parent and synthesized material were observed. This work achieved important improvement in the capacity retention of organic cathode materials and set the baselines for the future in the field.