Two C₁-symmetric heterohelicenes were constructed by nonsymmetrically extending the ortho-fused structures of a C_2v-symmetric NBN-embedded phenalene derivative and featured intense luminescence, large Stokes shifts, and successive reversible redox behaviors. Increasing one fused phenyl unit in such a helical structure led to a 10-fold-enhanced dissymmetry factor. Their strong double hydrogen-bond-donating capability makes them distinctly red-shifted in absorption, emission, and CD and CPL spectra upon the addition of fluoride anion.