NOVELTY - A composition (C1) comprises at least one polymer (P1) containing at least one first donor moiety and at least one specific first acceptor moiety; and optionally, where the donor comprises at least one fused ring system.    USE - As composition; as an ink composition; and as coated substrate is part of an organic electronic device which is an organic photovoltaic device (claimed).    ADVANTAGE - The coated substrate is part of an organic electronic device which is an organic photovoltaic device which provides a power conversion efficiency of at least 6, at least 7, at least 8% and Voc of at least 0.6, at least 0.7, 0.8 V or and Voc of at least 1 V. The composition has ability to control band gap and HOMO and LUMO levels, where the HOMO is shifted to more negative values. Thus it provides better air stability. The composition has polymer solubility at ambient or room temperature (25 degrees C), including good solubility with higher molecular weight polymers. This allows for easier processing and film formation. The composition includes possible S-F interactions that help to planarize the polymer backbone and/or improve charge mobility and chain packing.    DETAILED DESCRIPTION - A composition (C1) comprises at least one polymer (P1) containing at least one first donor moiety and at least one first acceptor moiety, where the first acceptor moiety comprises at least one moiety of formula (I); and optionally, where the donor comprises at least one fused ring system.    X1, X2, Y1 and Y2=C or N;and    Z'=bridging moiety comprising at least one carbon atom or heteroatom.    INDEPENDENT CLAIMS are included for the following:    (1) ink composition (C2) comprising the polymer (P1);    (2) method (M1) involving providing the moiety (I), and functionalizing the moiety (I) with at least two polymerization reaction sites;    (3) method (M2) involving providing monomer precursor comprising at least one first ring fused with at least one second ring, where the first ring comprises at least two polymerization reaction sites, functionalizing the monomer precursor with at least two fluorine atoms on the first or second ring to form the monomer; and    (4) composition (C3) comprising at least one copolymer containing at least one first donor moiety and at least one first acceptor moiety in the copolymer backbone, where the first acceptor moiety comprises at least one first ring which is bivalently linked to the copolymer backbone and at least one second ring fused to the first ring and not bivalently linked to the copolymer backbone, where the first acceptor moiety comprises at least one third ring which is fused to the first or the second ring, where the first ring or the second ring or the third ring comprises at least two adjacent fluoro ring substituents.