Abstract A series of donor–acceptor chromophores was prepared in which the spacer separating 4-dimethylanilino (DMA) donor and C (CN) 2 acceptor moieties is systematically varied. All of the new push–pull systems, except 4 b, are thermally stable molecules. In series a, the DMA rings are directly attached to the central spacer, whereas in series b additional acetylene moieties are inserted. X-ray crystal structures were obtained for ...