This report delves into the multifaceted aspects of Corporate Social Responsibility (CSR) and sustainability reporting, examining their increasing significance for companies with financial objectives. It begins with a literature review on CSR, highlighting its benefits, such as enhanced brand image and cost reduction, and its role in attracting investors and employees. The report then contrasts sustainability reporting with other reporting concepts, like Integrated Reporting (IR), emphasizing its holistic view of CSR, encompassing economic, ecological, and social aspects. Two key theories, Stakeholder Theory and Legitimacy Theory, are employed to explain sustainability reporting. The practical part of the report focuses on Smartgroup Corporation Industrials, analyzing its corporate governance and financial performance. A sustainability reporting scoring index, based on Global Reporting Initiative (GRI) guidelines, is developed and applied to assess the extent and quality of Smartgroup's sustainability reporting. The report concludes by evaluating Smartgroup's adherence to sustainability reporting standards.