AbstractNonaromatic luminophores without remarkable conjugates have aroused great attention. Their emission mechanism, however, remains an open question. Meanwhile, previous studies generally focus on aliphatic amine and/or carbonyl‐containing systems; those with merely oxygen moieties (i.e., ether, hydroxyl) are scarcely touched. Recently, the clustering‐triggered emission (CTE) mechanism is proposed to rationalize the emission of nonconventional luminophores, according to which compounds bearing purely oxygen moieties can also be emissive. To check this conjecture, herein, both nonaromatic compound of xylitol and polymers of PEG and F127 are studied, which are found to be emissive in concentrated solutions and solids. Furthermore, cryogenic‐persistent phosphorescence of the compounds and even persistent room temperature phosphorescence of xylitol crystals are observed. Additionally, their potential application as Fe3+ sensors is demonstrated. These results not only verify the rationality of the CTE mechanism but also suggest the possibility to discover and design new luminophores according to it.