Electrochemical proton pumps based on conductive polymers provide a promising route for localized pH modulation in analytical and environmental applications. In this work, we present a comparative study of polyaniline (PANI) and its copolymer, poly(aniline-co-o-aminophenol) (PANOA), focusing on their structural, morphological, and electrochemical properties, which are relevant to their proton pumping performance. The local microscopic variations in their surface topography, morphology and conductivity are studied by employing scanning electrochemical microscope (SECM), while detailed characterization using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) reveals significant differences in films’ porosity, stability, and doping behavior that directly influences their acidification efficiency and spatial proton distribution. PANI films with a porous, swelling-prone structure enable broad and intense proton release, but also complicate precise pH monitoring. In contrast, PANOA films demonstrate compact and morphologically stable structures, offering more localized and controllable pH modulation. To resolve the local proton gradients generated by these films, we employ a PANI-based ultramicroelectrode (UME) pH sensor integrated into a SECM platform, enabling micrometer-scale resolution of pH changes near the film surface. This approach offers a novel methodology for investigating interfacial proton dynamics and contributes to a deeper understanding of how polymer structure influences proton pump functionality. The dual application of PANI polymer as both a proton pump and a pH sensor demonstrates its versatility, providing valuable insights into the design of next-generation electrochemical platforms for pH modulation.