<p>A substitute product is one that can replace another product to fulfill identical client requirements. This study examines an imperfect manufacturing system, including rework, scrap, and defective items, utilizing advertisement-sales return and Cournot’s inverse linear demand as the demand function for Substitutable products, alongside optimal demand and green production lot size as decision variables in a third-order equation. The price BEP is established, the law of demand is validated, and the maximum potential profit is computed from the three alternate demands for the commodity. A comparative analysis is conducted between the reworking and non-reworking of defective items, concluding that reworking yields greater profit. A carbon fee and green investment technology expense are employed to mitigate carbon emissions. A comparative analysis is conducted between the reworking and non-reworking of defective items, concluding that reworking yields greater profit. A carbon fee and green investment technology expense are employed to mitigate carbon emissions. To my understanding, no writers have formulated a model for flawed manufacturing, reworking, scrap for Substitutable products for defective items, Reworking with utilizing advertisement-sales return-Cournot’s linear inverse demand as demand and optimal demand and green production lot size are decision variables. This study aims to maximize total profit by determining the ideal demand and production lot size. The applicability of this concept is illustrated by numerical examples. The overall profit is shown to be dependent on the degree of substitutability. To evaluate the stability of the suggested model, a sensitivity analysis of the best options is provided. Visual Basic 6.0 is used to generate the data.</p>