Polymorphic Organic Microcrystals for Multi‐Color Circularly Polarized Laser Emission

Circularly polarized lasers play important roles in chiroptical technologies. Organic materials have the potential for exploring multi‐color circularly polarized laser emission owing to their large diversity. However, the realization of multi‐color organic circularly polarized lasing generally requires sophisticated molecular design and time‐consuming synthesis. Here, we propose a crystal polymorphism strategy to realize multi‐color circularly polarized lasing. Three kinds of polymorphic microcrystals are synthesized from one organic compound by controlling the liquid‐phase molecular self‐assembly. The polymorphic microcrystals combine the cavity effect with multi‐color optical gain and chiroptical activity, which enable violet‐blue, blue, and cyan circularly polarized laser emission. This work establishes an organic polymorphic material platform for exploring multi‐color circularly polarized lasers.