Poly(quinoxaline-2,3-diyl)s containing (S)-3-octyloxymethyl side chains with low degree of polymerization exhibited M-helical conformations in cyclohexane, while the polymers with high low degree of polymerization adopt P-helical conformations. This bidirectional screw-sense induction can be rationalized based on a modified theoretical model, which includes the effect of the terminal groups. Furthermore, the authors also found that triblock copolymers that contain the chiral units either in the terminal groups or in the main chain adopted M- or P-helical conformations, respectively.