Zn[Formula: see text]-doped CTAB@BiOCl inorganic–organic composites were prepared by a co-precipitation method with different aging periods. The results show that the aging period has great influence on the structure, morphology and surface area of Zn[Formula: see text]-doped CTAB@BiOCl. The as-synthesized samples tend to form lamellar stacking structure with the increase of the aging time. In addition, the surface area and pore size distribution of samples decrease with the aging period from 0[Formula: see text]h to 48[Formula: see text]h and then increase from 48[Formula: see text]h to 96[Formula: see text]h. Besides, the content of CTAB in these composites increases along with the aging period from 0[Formula: see text]h to 3[Formula: see text]h and then decreases from 3[Formula: see text]h to 96[Formula: see text]h. Their photocatalytic performances were evaluated by the degradation of Reactive Red 3 (X3B) under UV light irradiation. It is found that the photocatalytic performance of composites increases with the prolonging of the aging time, and 100[Formula: see text]mg/L of X3B solution can be almost completely degraded within 16[Formula: see text]min by S[Formula: see text]. Moreover, the possible formation mechanism has been proposed and discussed in detail. The work can provide a new sight for broadening the application of co-precipitation in the preparation of nanomaterials and for in-situ one-step synthesis of inorganic–organic composites.