Magnetic susceptibility and electron paramagnetic resonance (EPR) spectra of exquisite two-dimensional supramolecular assembly of [bis(α- aminoisobutyrato)oxalamidodicopper](Aib-COCO-Aib)Cu 2 were studied. The temperature dependent magnetic susceptibility studies reveal temperature dependency of the exchange coupling constant. Single crystal EPR studies both at X- and Q-bands show the two-dimensional nature of magnetic lattice and yield the weak intermodular exchange coupling constant in presence of strong intramodular exchange. The intermodular coupling is about five orders of magnitude smaller than the intramodular coupling but it produces a broadening and coalescence of the EPR lines. The temperature dependence of exchange coupling constant reflects dynamical properties of the crystal lattice. © 2005 Elsevier B.V. All rights reserved.