Two polymeric [VO3]nn− metavanadate chain complexes have been synthesized and characterized by spectral and elemental analysis. The X-ray data of only complex 2 has been reported in this work. Both the complexes have a linear vanadate chain, countered by appropriately charged organic amine moieties. The simplest units of the chains contain a linear [V3O9]3− and [V2O6]2− anionic moieties in complexes 1 and 2, respectively. The charge neutralizing cationic counterparts are triprotonated tren {tris(2-aminoethyl)amine} and a diprotonated N-ethylethylenediamine in complexes 1 and 2, respectively. Complex 2 is unique in the sense that its crystal lattice contains the divanadate [V2O6]2− repeat unit and protonated N-ethylethylenediamine as the charge compensating and space filling moiety which is not reported in any other literature till now. The individual units are assembled to form a 2D supramolecular network. DFT calculations (PBE0-D3/def2-TZVP) have been used in combination to QTAIM and NCI plot computational tools to analyze the strong N–H···O charge assisted hydrogen bonding interactions in both complexes. Phenoxazinone synthase like activity (i.e. oxidative conversion of o-aminophenol to 2-aminophenoxazine-3-one) of complex 2 was evaluated.