A fan-shaped molecule (2), carrying hydrogen-bonding amide groups in proximity to its polar aromatic core, self-assembles into a columnar liquid crystalline mesophase, which unprecedentedly possesses a spontaneous macroscopic polarization along the columnar axis. Due to its polar nature, the mesophase displays a signal of second harmonic generation (SHG), which disappears on phase transition to an isotropic melt and then retrieves its original intensity on subsequent cooling.