In this paper we report on the calculation of the spin correlation function describing the dipolar spin-spin interaction for benzene and naphthalene in their lowest excited triplet state. Spin-coupled wave functions were used. The spin correlation function measures the contributions to the [3S(z)(2)-S-2] expectation value arising from electrons located at different points. An alternation of positive and negative correlation dependent on the separation of the unpaired electrons is found. The results are used to analyze and interpret the zero-field splitting parameter D of these molecules in terms of different contributions. The relationship between the spin correlation function and the sequence of the zero-field levels as well as the value of the parameter D and its dependence from molecular size is discussed. (C) 2001 American Institute of Physics.