The use of 4,4’-[oxalylbis(azanediyl)]bis(2-hydroxybenzoic acid) (H6L1) in the Ba2+ chemistry has afforded a 3D polymer, namely [Ba(H2L2)(H2O)](n) (1), which is based on H2L22- anions derived by the in-situ metal-assisted transformation of H6L1. The neutral H4L2 [4-(carboxyformamido)-2-hydroxybenzoic acid] ligand was isolated from 1 and characterized by spectroscopic methods. Polymer 1 is based on edge and facesharing BaO10 polyhedra which create an inorganic layer pillared to the third dimension by the organic ligands and has been classified as an (IO1)-O-2 framework. The topological analysis of 1 provided an opportunity to introduce a method for the deconstruction of (IO1)-O-2 frameworks by adopting principles applied in the deconstruction of Metal-Organic-Frameworks (MOFs) with rod Secondary Building Units (SBUs). A detailed discussion and insights for the proper use of the (IOn)-O-m notation which finds application in describing the dimensionality in MOFs, is also provided.