Based on chemical signed graph theory proposed by Lee et al. the novel information theoretic topological index, I-k, is derived from the edge signed graphs. Subsequently, based on the definition of I-k, few other properties based information theoretic indices such as, bonding information index, I-b, non-bonding information index, I-b, and anti-bonding information index, I-a, are also evaluated. Moreover, the index. I-b and I-a, are found to be useful in QSAR modeling of unsaturated hydrocarbons. (C) 2004 Elsevier B.V. All rights reserved.