This chapter examines how the changes from voluntary to mandatory corporate social responsibility (CSR) reporting influence the quantity and quality of disclosed CSR information. Furthermore, it examines the adaptation level for CSR reports in relation to the requirements of the regulatory regime. To do so, a research agenda is designed through the relative literature in order to make clear the challenges and barriers of the changes of the CSR reporting regime as well as a framework is developed to evaluate the progress of CSR reports within the new regime. This research is based on a scoring and benchmarking methodology which is tested in a sample of 23 Greek firms which systematically publish CSR reports the last five years. It is worth noting that a mandatory regime from CSR reporting has been lately introduced in Greece by integrating into Greek Law (4403/2016) the European Union Directive 2014/95/EU which requires Greek firms with over 10 employees to publish CSR reports on a mandatory basis.