Copper(I) complexes for the emission of light with a structure according to formula A: wherein: M is Cu(I); L-B-L: a neutral, bidentate ligand, Z4-Z7: includes N or the fragment CR, with R=organic group, selected from the group consisting of: hydrogen, halogen or deuterium or groups which are bound via oxygen (—OR′″), nitrogen (—NR′″2), or phosphorous atoms (PR′″2) as well as alkyl, aryl, heteroaryl, alkenyl, alkinyl, trialkylsilyl and triarylsilyl groups or substituted alkyl, aryl, heteroaryl and alkenyl groups with substituents such as halogens or deuterium or lower alkyl groups; X is either CR′″2 or NR′″; Y is either O, S or NR′″; Z8 includes the fragment CR′, with R′=O*R′″, N*R′″2 or P*R′″2, wherein the bond to the Cu atom is carried out via these groups; R″ is a sterically demanding substituent, which inhibits a change in geometry in direction to planarization of the complex in excited state, R′″=organic group which is selected from the group consisting of: hydrogen, halogen or deuterium, as well as alkyl, aryl, heteroaryl, alkenyl, alkinyl groups or substituted alkyl, aryl, heteroaryl and alkenyl groups with substituents such as halogens or deuterium, alkyl groups, and further generally known donor and acceptor groups * indicates the atom which receives the complex bond; and # indicates the atom which mediates the bond with the second chemical unit.