Mesoporous poly(Tannic Acid)-Silica nanoparticle composites (p(TA)-Si NPs) were prepared via one pot reaction. At various TA amounts in feed, 50,100, 250, 500, 1000 mg at different reaction times, 2, 4, 8,12, 24 h in the presence of TEOS and epoxy crosslinker, trimethylolpropane triglycidyl ether (TMPGDE), NPs composites were readily prepared. The prepared p(TA)-Si NPs by using 1000 mg TA at 12 h reaction time at room temperature as p(TA)1000-Si NPs provided the highest yield (similar to 48%). The particle size, monodispersity, specific surface area, porosity, and the gravimetric yields are greatly depended on initial TA concentration and reaction time. The particles sizes were found as 237-445 nm depending on TA content and reaction time. The highest surface area was measured as 872 m(2)/g for p(TA)1000-Si NPs for 2 h reaction time. The thermal stability of p(TA)-Si NPs decreased as TA content is increased. Interestingly, p(TA)1000-Si NPs are found effective antioxidant materials. (C) 2016 Elsevier Inc. All rights reserved.