Pentagon is research and innovation project that investigate the potential of wider deployment of energy conversion technologies and strategies at district-level, with the aim to foster flexibility in the low-voltage and medium-voltage grid. Multi-vector smart districts can be the key enablers of future smart grids, provided their flexibility capabilities are augmented with adequate energy conversion technologies. Object of the research are two key technologies: a highly efficient power-to-gas installation sized for coupling with typical district heating plants and a multi-vector multi-scale district energy management platform for the combined monitoring and management of all district energy carriers.