A new cobalt(II) complex [Co(NO2-salen)2]·1.5H2O containing mono acetalization Schiff base ligand(NO2-salen = N-5-nitro-salicylideneamino ethanato) has been prepared through one-pot template condensation, and has been structurally characterized by elemental analysis, IR spectra and X-ray diffraction. It is formulated as C18H23CoN6O7.5, crystallizes in the hexagonal system, space group of R-3c with α = 25.895(18), b = 25.895(18), c = 35.075(6), γ = 120o, V = 20368(3) and Z = 36. The ligand of 5-nitrosalicylaldehyde-ethylene-diamine takes unusual mono asymmetry mode. The Co(II) ion exhibits a coordination number of six, and assumes a distorted octahedral geometry with a N2O4 donor set. The neutral monomeric units of [Co(NO2-salen)2]·1.5H2O are linked into a one-dimensional(1D) structure via the intermolecular hydrogen bonds and weak π-π stacking interactions. Cyclic-voltammetry measurement reveals the oxidation and reduction processes for the complex are irreversible in nature. A new cobalt (II) complex [Co (NO2-salen) 2] 1.5H2O containing mono acetalization Schiff base ligand has been prepared through one-pot template condensation, and It has been structurally characterized by elemental analysis, IR spectra and X-ray diffraction. It is formulated as C18H23CoN6O7.5 crystallized in the hexagonal system, space group of R-3c with a = 25.895 (18), b = 25.895 The ligand of 5-nitrosalicylaldehyde-ethylene-diamine for unusual mono-asymmetry mode. The Co (II) ion exhibits a coordination number of six, and assuming a distorted octahedral geometry with a N2O4 donor set. The neutral monomeric units of [Co (NO2-salen) 2] · 1.5H2O are linked into a one-dimensional (1D) structure via the intermolecular hydrogen bonds and weak π-π stacking interactions. Cyclic-voltammetry measurement reveals the oxidation and reduction processes for the complex are irreversible in natur e.