n conclusion, we demonstrate that the mesoporous silica nanoparticles can be employed as an encapsulation material for the encapsulation of a commercially available and industrially used OB, 4,4′-distyrylbiphenyl sulfonate sodium salt (CBSX). The results show the high encapsulation efficiency and excellent pH responsiveness. The optical bleaching of cellulose fabrics with CBSX-loaded PEM-MSNP nanocontainers at neutral pH revealed high whiteness index and total color change. This study manifests the potential of mesoporous silica based inorganic-polymer hybrids as next generation smart nanosized delivery vehicles for the pH-controlled optical bleaching of cellulose fabrics