<p>Circularly polarized luminescence (CPL) is
important to chiral photonic technologies. In the molecular systems, besides
their intrinsic chemical structures, the architectures of molecular assemblies
at the mesoscopic scale also account for the final macroscopic CPL properties.
Herein, tunable CPL responses can be induced through architectural regulation
of these molecular assemblies in suspension and solid states. A liquid
crystalline assembled system of DPCE-ECh exhibiting smectic C* phase with a
high dissymmetry factor (<i>g</i><sub>CD</sub>
= -0.20 and <i>g</i><sub>lum</sub> = +0.38)
is reported. The intense and apparent
CD and CPL of the film stem from the intrinsic helical structure of the
molecular assembles with<b> </b>weak<b> </b>contribution of Bragg reflection,
where the helical axis is perpendicular to the optical axis and is parallel to the direction of the
glass substrate. To the best of our knowledge,<b> </b>this large <i>g</i><sub>lum</sub> factor is very rare for
organic compounds even in the assembled state formed by annealing at smectic
liquid crystalline temperature. Interestingly, strong
CPL signal with <i>g</i><sub>lum</sub> value
of +0.18 is still recorded when DPCE-ECh is annealed at chiral isotropic liquid (Iso*) state. On the other hand, DPCE-ACh can form two coexistence
phases of chiral hexagonal and smectic liquid-crystalline phases due to
intermolecular hydrogen bonding. The non-periodic
molecular orientations of DPCE-ACh break itself helical structure to give a
weak negtive CPL signal in 10<sup>-3</sup> order. This work thus
provides a new insight for developing efficient chiroptical materials in the
aggregate state and profound implications in high-performance CPL-based device.</p>
Tunable circularly polarized luminescence from molecular assemblies of chiral AIEgens