Doping at nanoscale and modification of nanocrystal either by binding or interaction is possible if the morphology of the nanocrystal and the properties of the dopant present in the chemical solution are exactly known [30,31]. In other words, the binding energy of the impurity/dopant with respect to the surface of the host lattice, the bonding character and the coordination environment have role to affect the microstructure, grain boundary distribution, surface, optical and photo-catalytic properties of doped materials. In view of this, we adopted a modified so-gel technique, where dopants (Ag and Ni) are present in the chemical solution for the effective doping in the host matrix. However, the literature reports generally involves higher doping concentrations of these ions, but the novelty of the present work lies in the case specific study of a single and nominal doping concentrations of 0.02 wt.% Ag and Ni in TiO2, which has led to unusual changes with respect to its microstructure, grain boundary distribution, pore size distribution and surface properties, optical and photo-catalytic activity towards complete degradation of organic pollutant dye within few minutes of visible and UV light irradiation. (C) 2010 Elsevier B.V. All rights reserved.