Journal of Mathematics, cilt.2026, sa.1, 2026 (SCI-Expanded, Scopus)
In this article, the first eccentricity connectivity coindex is introduced as (Formula presented.), in which ε(u) denotes the eccentricity of the vertex u in the simple connected graph G. Then, the exact expressions are obtained for the first eccentricity connectivity coindex of some graph products. To evaluate the effects of eccentricity-based indices and coindices in QSPR studies, an analysis was performed with physicochemical properties of octane and its isomers. A nonlinear model was developed using the QSPR approach to predict the determined properties, and the results showed that the indices exhibited satisfactory performance in comparative tests especially for the AF property.