The organ of UN that promotes voluntary co-operation among member states in diverse areas is the

The organ of the United Nations that promotes voluntary cooperation among member states in diverse areas is the "Economic and Social Council" (ECOSOC). ECOSOC is responsible for promoting sustainable development, improving living standards, and addressing economic, social, and humanitarian issues. It serves as a forum for member states to discuss and coordinate their economic and social policies, and to develop and implement international agreements in these areas. ECOSOC has 54 members, which are elected by the General Assembly for three-year terms. It meets regularly throughout the year, and also convenes special sessions and conferences on specific issues. Overall, ECOSOC plays a key role in promoting international cooperation and addressing global challenges in areas such as poverty, health, education, and human rights.