Let us imagine a mix of corporate responsibility with constitutional values in order to bring up change in society. The paper is about how Corporate Social Responsibility (CSR) affects social and environmental welfare, especially given the mandatory Corporate Social Responsibility of India and the voluntary, Constitution-based Corporate Social Responsibility of Brazil. The Indian model as prescribed by statutory provisions of the Companies Act of 2013 provided for company contributions to public good in education, health, and rural development above all under institutionalized CSR compliance with constitutional provisions of social justice in absolute deviation to the looser CSR framework in Brazil farfetched from the 1988 Constitution, which emphasizes rather corporate freedommore of a labor right, biodiversity, social inclusion without any stringent regulatory mandates. The comparative analysis lies in both strengths and challenges for each of the two models structured compliance to the innovative but still overly illustrative engagement of Brazil in this case. Real-case studies like Tata Group and Vedanta Resources in India and Petrobras and Natura & Co in Brazil show how practices of CSR imply within these countries. The article describes the concept of constitutionalism for sustainable development and in further terms carries on reforms towards more effective outcome-based CSR in keeping with national priorities to build up inclusive growth and ecosystem-friendly development. The comparative leg between corporate social responsibility and duty of obligation in the Constitution creates an advancement towards a far more equitable and sustainable future.