Following the ECMolS held in Bologna (2016) and in Peniscola (2018), ECMolS20 has the goal to gather the community working in the field of molecular spintronics, that comprises the following research areas: organic spintronics, molecular electronics, molecular magnetism and molecular quantum technologies. In addition to these traditional topics, the third ECMolS edition is even open to scientists investigating 2D materials, with special focus on proximity effects at the interface between two material layers - including, of course, interfaces with molecular systems.