With the aim of exploring the electronic properties of new material in view of potential applications, a density functional theory study of five systems made up of reference systems thiophene and hexa-fluoro phenyl arranged in different ways is presented. Energy, chemical potential, molecular hardness, electrophilicity and polarizability are studied and rationalized in term of the relative position of the building units. It has been found that although the chemical potential and hardness do not change dramatically with respect to the reference systems, the reactivity of the resulting composite systems is highly enhanced. (c) 2006 Elsevier B.V. All rights reserved.