Herein we report a novel host-guest complex single crystal material based on a pillar[5]arene (PS) and a laser dye trans-4-[p-(dimethylamino)styryl]-1-methylpyridinium iodide (DASP). Single crystal structure characterization shows that two PS molecules act as a supramolecular nanocapsule for one isolated DASP molecule. This spatial confinement effectively restricts aggregation-caused quenching (ACQ) effects and other nonradiative channels (e.g., twisted intramolecular charge transfer), leading to high luminescent efficiency of the isolated DASP. Together with its regular shape and smooth surface, each 2P5 superset of DASP microcrystal forms a Fabry-Perot (F-P) microcavity and produces a stable laser output with a high Q factor and a low threshold.