NOVELTY - Use of a mixture (comprising one or more fused heterocyclic compounds (k1) as electron donor or electron acceptor, and one or more compounds (k2) acting as electron acceptor or electron donor with respect to (k1)) for producing photoactive layers for organic solar cells and organic photodetectors, is claimed.    USE - The mixture is useful for: producing photoactive layers for organic solar cells and organic photodetectors (claimed); and the production of electronic devices based on organic semiconductor layers, such as organic field effect transistors and organic light emitting diodes, which are useful in displays and organic photovoltaics.    ADVANTAGE - The mixture provides the photoactive layers for organic solar cells and organic photodetectors in an economical and simple manner, and the produced cells have improved energy conversion rate, compactability and flexibility.    DETAILED DESCRIPTION - Use of a mixture (comprising one or more fused heterocyclic compounds (k1) of formula (a)-(g) as electron donor or electron acceptor, and one or more compounds (k2) acting as electron acceptor or electron donor with respect to (k1)) for producing photoactive layers for organic solar cells and organic photodetectors, is claimed.    A = bridge comprising two or three sp3-hybridized carbon atom, which is optionally substituted with R101, and optionally benzofused;    B1, C1 = bridge comprising two or three sp2- and/or sp3-hybridized carbon atom, which is optionally substituted with R101;    W1 = O, S, N-CN, N-R110, C(CN)2, C(CO2R110)2, C(CN)COR110, C(CN)CO2R110 or C(CN)CONR110;    L = bivalent, optionally one or more times annelated carbo- or hetero-cycle;    n = 0 or 1;    X100 = CH, N or C(CN);    X200 = C(R111)2, O, S, SO2 or NR110;    X201 = CR111 or a sp2-hybridized, unsubstituted carbon atom, where X201 is bounded with a sp2-hybridized carbon atom of the bridge-B1 or -C1;    R100 = H, alkyl, 1-6C-alkylene-COO-alkyl, 1-6C-alkylene-O-CO-alkyl, 1-6C-alkylene-O-CO-O-alkyl, cylcloalkyl, arylalkyl, aryl, OR110, SR110, heteroaryl, halo, NO2 or CN;    R101 = alkyl, 1-6C-alkylene-COO-alkyl, 1-6C-alkylene-O-CO-alkyl, 1-6C-alkylene-O-CO-O-alkyl, cylcloalkyl, arylalkyl or (hetero)aryl;    R110 = H, alkyl, 1-6C-alkylene-COO-alkyl, 1-6C-alkylene-O-CO-alkyl, 1-6C-alkylene-O-CO-O-alkyl, cylcloalkyl, arylalkyl or aryl; and    R111 = H, alkyl, 1-6C-alkylene-COO-alkyl, 1-6C-alkylene-O-CO-alkyl, 1-6C-alkylene-O-CO-O-alkyl, cylcloalkyl, arylalkyl or (hetero)aryl, where the carbon chains of alkyl- and cylcloalkyl-radicals are optionally interrupted by one or two non-adjacent oxygen atoms.    An INDEPENDENT CLAIM is included for producing photoactive layers comprising vacuum deposition of the components (k1) and (k2) on a substrate in a simultaneous, sequential or in an alternative manner.