The advent of polymer (or plastic) optical fibers (POFs) with porous cross-section has contributed significantly to the sensing applications. We intend to explore the sensing attributes of polymer-based one-rod core microstructured optical fibers (P-MOFs) via utilizing an auxiliary approach. The sensitivity coefficient and the overlapping factor of P-MOF’s introduced design in air-filled and water-filled layouts against the structural parameters are exploited. We reported the overlapping factor of ~ 94% and ~ 82% for the said configurations of the fibers, respectively, at the wavelength of 0.633 µm. The confinement loss, mode-index, and effective mode-area are also evaluated for the anticipated structures. For assessing the confinement loss, an alternative approach based on double-clad fiber (DCF) approximation is employed. The validity of the simulated results is scrutinized with those as documented in the literature. Relative errors are also tabulated.