AbstractGlassy materials, with desirable mechanical rigidity, shaping ability, high transparency, are attracting great interest in diverse fields. However, optically bulk molecule‐based glasses are still rare, mainly due to limited monomeric species and harsh preparation conditions. Herein, we report a facile bottom‐up solution fabrication process to obtain metal‐free supramolecular glasses (SMGs) at the macroscopic scale using L‐Histidine and hexamethylenetetramine as building blocks. The chiral SMGs possess color‐tunable ultralong room temperature phosphorescence (decay lifetime up to 141.2 ms) and circular polarized luminescence (g factor up to 8.7×10−3). The strong hydrogen bonds effectively drive the formation of SMGs, and provide a rigid microenvironment to boost triplet exciton generation. By virtue of excitation‐ and temperature‐dependent ultralong phosphorescence of the SMGs, applications including multicolored displays, visual UV detection, and persistently luminescent thermometer are demonstrated.