In this study, we give some theoretical results for studying the structural connectivity of oligothiophene dendrimer by utilizing the neighborhood M-polynomial. The main result of this article presents the closed formula of neighborhood M-polynomial of oligothiophene dendrimer which is used for computing the neighborhood topological indices of the dendrimer. Among the various indices considered, the forgotten index obtained the highest value, followed by the Sanskruti index, first Zagreb index, and second Zagreb index. These topological indices exhibited an increasing trend as the number of generation increases across the dendrimer structure. Conversely, the remaining index values display minimal or negligible changes as the generation increases. This suggests that these indices exhibits slow increases with higher generations in the dendrimer structure. The significance of adopting the neighborhood M-polynomial to compute the topological index lies in the fact that it facilitates the analysis of complex molecules in a timely manner and allows pendant vertex to contribute more effectively to the overall degree value of the dendrimer. Furthermore, the dataset resulting from these topological indices serves as a foundation for future studies aimed at predicting the physicochemical properties of the dendrimer.