A pillared layer network containing amide functional groups (Cu(pzdc)(pia); pzdc = pyrazine-2,3-dicarboxylate; pia = N-(4-pyridyl)isonicotinamide) was used to test a postsynthesis metalation rationale to insert lithium and create a porous surface with enhanced CO2 adsorption capacity. Synchrotron powder X-ray diffraction (XRD) was used to determine variations after lithiation in long-range and textural properties. CO2 adsorption measurements at room temperature showed a concave up isotherm shape with an increasing adsorption at high pressures, surpassing by 1 order of magnitude the values previously reported for the unmodified material. There was significant hysteresis upon desorption, which suggests structural variations consequent to different or stronger adsorption sites. Results from elemental, thermal gravimetric, and crystal refinement analyses indicate that the lithium content is ca. 3 Li atoms per asymmetric unit. Raman scattering showed N–Li and Li–O stretching bands, a shift of pia amide- and pyridyl-related bands, and other significant skeletal vibrations associated with nitrogen and oxygen lone pair variations. In situ XRD and CO2 adsorption observations at up to 50 bar at ambient temperature were consistent with the anticipated structural dynamic variation. The lattice changes observed at pressures below 10 bar following lithiation may be directly related to an enhancement in the CO2 adsorption amount.