A novel hybrid mesoporous silica-Mn-porphyrin nanomaterial and its application for fluorescent detection of H2O2 is reported. The hybrid was obtained by sol-gel method in two steps acid-base catalysis and was completely characterized by UV-vis, FT-IR, fluorimetric, DRX, BET, AFM, TEM and conductivity investigations. The influence of adding H2O2 to the silica-Mn-porphyrin hybrid generates major differences regarding the optical, textural and morphological properties of the material. The dependence between H2O2 concentration and the fluorescence intensity, measured at the emission maximum at the wavelength 655 nm, is linear with an excellent correlation coefficient of 0.9945. The high sensitivity for hydrogen peroxide in wet media noticed for this hybrid, accompanied by changes in color, justifies further investigations towards design of fluorimetric and colorimetric O-2 gas sensors. The low conductivity of the manganese(III)porphyrin-silica hybrid (0.694 x 10(-8) S/cm) can be improved, so that this material may become a promising one for electrochemical cells (batteries). (C) 2015 Elsevier Ltd. All rights reserved.