The 2nd International online Conference on Construction Materials for a Sustainable Future CoMS 2020/21 was held on April 20 and 21 2021. CoMS conference was attended by more than 130 worldwide experts coming from 19 different, mostly European, countries. The conference focused on the sustainable development of the construction sector, which is one of the important factors in achieving the EU's climate change objectives. CoMS 2020/21 conference was organized by ZAG and partners. Programme was composed of six plenary and eight keynote lectures, 58 oral presentations and 16 posters. Conference Proceedings were published in two volumes,with volume one including 40 papers and volume two 20 papers.