This study presents the synthesis, structural characterization, and investigation of the photochromic properties of two Zn-coordination polymers, formulated as {(HV)0.5[Zn(MIC)(HMIC)]·H2O}n (1) and {(HV)2[Zn4(BTEC)3]}n (2) (H2MIC = 5-methylisophthalic acid, H4BTEC = 1,2,4,5-benzenetetracarboxylic acid, HVBr2 = 1,1′-bis(n-hexyl)-4,4′-bipyridinium dibromide), derived from hexyl viologen cations. Compound 1 is characterized by a one-dimensional (1D) structure, while compound 2 exhibits a three-dimensional (3D) architecture, both crystallizing in distinct space groups and showcasing unique assembly and composition. Detailed structural analysis reveals the coordination modes of Zn(II) ions within these polymers. The photochromic behavior of two compounds under UV light exposure was thoroughly examined through ultraviolet-visible (UV–vis) and electron paramagnetic resonance (EPR) spectroscopy, demonstrating reversible color changes from light yellow to blue upon irradiation, with distinct rates of decolorization indicative of the stability of photo-induced viologen radicals. This reversibility was successfully replicated over multiple cycles, underscoring the durability of the photochromic transition. Furthermore, powder X-ray diffraction (PXRD) data confirmed the maintenance of crystal structures throughout the photochromic process, dismissing photolysis or photo-induced isomerization as underlying mechanisms. Instead, the observed photochromism is attributed to efficient electron transfer facilitated by the proximity between electron-donating and electron-withdrawing groups within the coordination polymers. This study highlights the influence of structural parameters on the photochromic properties of viologen-based coordination polymers, offering insights into the design of photo-responsive materials.