The paper presents a new method for activation energy or the Arrhenius parameter E, of the thermolysis in the condensed state for different polynitro arenes as an important class of energetic molecules. The methodology assumes that E. of a polynitro arene with general formula CaHbNcOd can be expressed as a function of optimized elemental composition as well as the contribution of specific molecular structural parameters. The new method can predict E, of the thermolysis under conditions of Soviet Manometric Method (SMM), which can be related to the other convenient methods. The new correlation has the root mean square (rms) and the average deviations of 13.79 and 11.94 kJ/mol, respectively, for 20 polynitro arenes with different molecular structures. The proposed new method can also be used to predict E. of three polynitro arenes, i.e. 2,2',2",4,4',4",6,6',6"-nonanitro-1,1':3'1'-terphenyl (NONA), 3,3'-diamino-2,2',4,4',6,6'-hexanitro-1,1'-biphenyl-3,3'-diamine (DIPAM) and N,N-bis(2,4-dinitrophenyl)-2,4,6-trinitroaniline (NTFA), which have complex molecular structures. (c) 2008 Elsevier B.V. All rights reserved.