The tetraethylammonium tetramethylammonium tetrabromocuprate(II), (hereafter, [(TEA)(TMA)CuBr4]) [(C2H5)4N][(CH3)4N][CuBr4], complex was synthesized and characterized by spectroscopic (IR), structural (XRD) and electron paramagnetic resonance (EPR) technique. The compound contains four isolated and discrete moieties, i.e. two independent [(CH3)4N]+ cations, with one on a -4 axis and the other with the central N atom on a 2z axis, one [(C2H5)4N]]+ cation, on a mirror plane and in a trans conformation, and one distorted tetrahedral [CuBr4]2– anion on another mirror plane. The electron paramagnetic resonance spectra of [(TEA)(TMA)CuBr4] single crystals and powder were investigated in the temperature range from 300 to 5 K. The observed values from the line width and g tensors were found to be temperature dependent. The temperature dependence of Cu(II) complex with EPR spectra values were also discussed in terms of dynamic Jahn-Teller effect.