Condensation of bis(ethanediamine)copper(II) perchlorate with formaldehyde and nitroethane in basic methanol was found to generate (1,9-diamino-5-methyl-5-nitro-3,7-diazanonane)copper(II) perchlorate, [Cu(L1)](ClO4)2. The copper(II) complex was characterized by elemental analysis and infrared and electronic spectra studies. The structure of [Cu(L1)](ClO4)2 was determined by X-ray diffraction. The crystal structure revealed that the copper ion is in an elongated octahedral coordination with four nitrogens at the equational position and perchlorate anions at the axial positions and that one of the perchlorate anions bridges two copper ions, leading to a linear polymeric structure in the crystal.