The development of selective and robust sensors for gases and VOCs requires material platforms capable of bridging molecular-level recognition with macroscopic electrical transduction. In this work, we present a rational design approach that couples molecularly imprinted polymer nanoparticles (MIP-NPs)—tailored for analytes of markedly different polarity—with conductive electrospun nanofibres based on MWCNT-loaded polymers. This combined strategy enables control over the sensing mechanism by orchestrating the chemistry, morphology and dielectric behaviour of the hybrid material. Although synthesised from identical monomers and crosslinkers, MIP-NPs imprinted for non-polar (e.g., terpene-like) templates and for highly polar analytes (NH₃/NH₄⁺) display pronounced differences in size, external functional-group distribution and surface polarity. These variations govern their compatibility with host polymers, their degree of dispersion or clustering within nanofibres, and ultimately their ability to perturb MWCNT percolation pathways upon analyte adsorption. The hosting polymers—PVP, PAN and PMMA—were selected for their contrasting hydrophilicity, water-uptake behaviour, and dielectric responses, offering an opportunity to tailor key aspects of the sensing architecture: fibre diameter (150–600 nm), surface roughness , nanoparticle localisation, MWCNT connectivity, and analyte diffusion under variable humidity. SEM and SEM-TEM analyses show that hydrophobic MIP-NPs distribute uniformly within PVP and PMMA fibres, whereas NH₃-imprinted NPs, being more polar, tend to form heterogeneous domains in hydrophilic matrices, enhancing local swelling and dielectric modulation. Gas-sensing tests under controlled humidity (40–70% RH) reveal that the measured electrical response emerges from a synergistic interplay between MIP-driven molecular recognition, polymer-specific affinity toward water and analytes, and the nanofibrous architecture that mediates MWCNT conduction. Non-polar VOCs primarily influence matrix–CNT interactions, while NH₃ induces stronger dielectric, swelling and humidity-coupled effects, particularly in hydrophilic hosts. Overall, this study demonstrates that rational materials design—integrating MIP chemistry, polymer physics and nanofibre morphology—provides a versatile route to engineer selective gas/VOC sensors, enabling tunable responses across a broad polarity and humidity range.