Mesoporous TiO2 nanoparticles were synthesised by varying solvothermal temperatures and synthesis pH. This work is focused on the morphology evolution of triphase mesoporous TiO2 in terms of lattice defects of crystallographic planes. Structural anisotropy of the prepared titania was observed to be enhanced with an increment of synthesis pH. The prepared material was proven to be a better photocatalyst (efficiency > 99.5% in 80 min) than single-phase anatase titania. The prepared photocatalyst will be very useful for the degradation of organic pollutants in wastewater to protect the environment.