Increasing levels of carbon dioxide in the atmosphere is currently a serious issue, so environment-friendly industrial methods are being developed to reduce it during production. For a supply chain including a manufacturer and a dealer, this research developed a model to determine combined profitable inventory policies with investment in sustainable technologies. A supply chain model (SCM) is being created to demonstrate the combined effect of the manufacturer’s time-dependent production rate and the dealer’s time-varying deterioration of items. The manufacturer enables dual choices for payments to the dealer, such as an early payment with a reduced product price and a delayed payment with an increased product price. The objective of this study is to address the best policies to maximize the profit for the whole supply chain. Both early and delayed payment cases are compared with applications of sustainability-based investments. Discussion about non-sustainable investment outcomes is also included in this study. Sensitivity analysis of the model is also done with variations in the input parameters. The model is demonstrated using an illustrated numerical example, a visual representation, and managerial insights.