The invention relates to a system for use in an electric or optical device comprising at least two organic or metallo-organic energy and/or charge variable moieties having conjugated unsaturated bonds, wherein at least one moiety has an energy state different from another of said moieties, characterized in that the system is a H-donor-Hacceptor system comprising at least one H-donor molecule having at least two hydrogen bonding clusters, each cluster comprising at least two groups having formed a hydrogen bond, and at least two H-acceptor molecules, each having at least one hydrogen bonding cluster, each cluster comprising at least two groups having formed a hydrogen bond with the groups of the H-donor molecule, at least one of the H-donor and H-acceptor molecules 10 further comprising one or more of the organic or metallo-organic energy and/or charge variable moieties.