2-[5′-N-(3-triethoxysilyl)propylurea-2′-hydroxyphenyl]-benzothiazole (HBTNH2) was covalently bonded to the inner surface of amorphous silica nanoparticles and unmodified and Al-doped mesoporous structured silicate, MCM-41 and (Al)MCM-41, respectively. The photodynamics of these materials was investigated using steady-state and femtosecond fluorescence up-conversion techniques. The guest molecule shows emission dependence on the excitation wavelength. Covalently bonding HBTNH2 to silica nanoparticles affects both the spectral and the dynamical behavior of the dye. The dual-band fluorescence and ultrafast dynamics indicate the possibilities for an excited-state intermolecular proton-transfer reaction between the dye and the silica framework. The observed behavior is assigned to contribution from excited populations of enol, keto, and anion forms. The excited-state dynamics and the emission spectra of the HBTNH2−MCM-41 material clearly reflect the confinement effect imposed by the MCM-41 nanochannels. Furthe...