The quasi-two-dimensional magnetism in the layered transition metal compound (CnH2n+1NH3)(2)CuCl4 (n = 10, 14) was investigated by means of electron paramagnetic resonance (EPR) and superconducting quantum interference device measurements. As a result, the high temperature magnetic phase transitions were reflected in the EPR parameters in a sensitive manner. (C) 2003 Elsevier B.V. All rights reserved.