A new chromium(III)-based infinite coordination polymer (ICP) was synthesized under solvothermal conditions. The morphology, particle size and the textural porosity of the resulting solids could be monitored and controlled by adjusting the volume ratio of the solvent mixture (1,4-dioxane/N,N′-dimethylformamide). Two differently textured samples were further compared using powder X-ray diffraction, scanning electron microscopy, FT-IR spectroscopy, solid-state UV-Vis spectroscopy and thermogravimetric analysis. Their sorption capacities for H₂, CO₂ and CH₄ were measured by using volumetric gas adsorption, while the isosteric heats of adsorption for the same gasses were calculated based on gas sorption data at different temperatures. Both samples showed a remarkable selectivity for CO₂ over CH₄ at 273 K. H₂ and CO₂ sorption capacities, (respectively 16.9 mg g⁻¹ at 77 K and 817 mm Hg and 168 mg g⁻¹ at 273 K and 760 mm Hg) of the sample composed of the nanosized particles, are comparable or even superior to values reported for most MOFs and ZIFs under similar conditions.