Circularly Polarized Luminescence from Chiral Supramolecular Polymer and Seeding Effect

H‐bonding driven J‐type aggregation and cooperative supramolecular polymerization of a sulfur‐substituted chiral naphthalene‐diimide (NDI)‐derivative ( S , S )‐NDI‐2 in decane leads to remarkable enhancement of fluorescence quantum yield (43.3 % from 0.5 % in the monomeric state) and intense CPL signal in the aggregated state with a high luminescence dissymmetry factor ( g lum ) of 4.6×10 −2 . A mixture of NDI‐2 with a structurally similar NDI‐derivative NDI‐1 (mixture of racemic ( S , S )‐ and ( R , R )‐ isomers and the achiral derivative) in 1:9 (NDI‐2/NDI‐1) ratio, when heated and slowly cooled to room temperature, showed no enhanced CD band, indicating lack of any preferential helicity. However, when a monomeric solution of the NDI‐1 in tetrahydrofuran (THF) was injected to preformed seed of NDI‐2 in decane, a prominent CD signal appeared, indicating chiral amplification resulting in induced CPL with high g lum value of 2.0×10 −2 from mostly (>98.5 %) diastereomeric mixture.