In this paper, we calculate and investigate the Nirmala coindex, first inverse Nirmala coindex and second inverse Nirmala coindex for the silicon carbide molecular network \(Si_2C_3\) -I[p; q] by using its corresponding CoM-polynomial. Furthermore, new entropy measures based on these coindices are proposed to quantify the topological complexity of the network. The results reveal consistent correlations between network parameters (p, q) and entropy growth, reflecting increased structural irregularity and information content with molecular size. These findings suggest that Nirmala coindex-based entropies can serve as valuable descriptors for assessing physicochemical properties such as hardness, electrical conductivity, and catalytic activity in silicon-carbon materials.
