This research used carbenicillin-based substituted indanyl acrylate copolymers to find solutions for seaside mild steel designs. Electrochemical corrosion analysis is used to analyze glycoside and vinyl-2-pyrrolidone acrylate condensed 5-indanyl methacrylate copolymers, as well as for weight loss, inhibition in saltwater, and theoretical density-functional theory. The DFT study revealed that both copolymers are eco-friendly, with significant transmitted electrons (N = 0.369), and showed similar FTIR peaks. The weight loss of mild steel (MS) observed from 0.375 to 0.638 g indicated corrosion in natural saltwater. Both copolymers of indanyl acrylates weight loss trials resulted in decreased weight loss (0.46�0.65 g/50 ppm) after 48 h. Then, the surface morphology of the MS before and after corrosion. Vinyl-2-pyrrolidone condensed 1:1 copolymer showed low corrosion in sea water. Furthermore, using electrochemical techniques, this research examined the coating efficiency of different mole ratios of 4:1, 1:1, and 1:4 copolymers in 3.5 NaCl. The Tafel result revealed the coated samples corrosion rate from 9.99 to 30.32 mm/y and observed the efficiency of a 1:1 pyrrolidone condensed copolymer. Nyquist copolymer semicircles are nearly reaching the real value region, with inhibition efficiency percentages between 80 and 83. Based on coating efficiency, 1:1 NVPIMA thermal stability was analyzed using thermogravimetric analysis and showed the highest Tg of 452.61 oC with low volatility. This work demonstrated the effectiveness of our polymers, along with the cyclic CON- and epoxy ring electron-donating tendency, in controlling mild steel corrosion through either complexation or adsorption mechanisms, in line with theoretical results. © 2025 Elsevier B.V., All rights reserved.