A simple, rapid, and one step microwave assisted synthesis of high-performance TiO2 nanoparticles within 15 min without using any post annealing treatment. The microwave irradiation power is varied from 180-900 W. The effect of microwave power on the structural, surface morphology, optical and photocatalytic activity has been systematically investigated. Powder XRD results suggest that TiO2 tetragonal with anatase phase formed directly during the microwave irradiation process. Spherical shaped morphology with average diameter of around 25-40 nm was observed by TEM images, which is good agreement with the grain size estimated from XRD. A considerable red shift in the absorption edge and decreasing the band gap (3.25-2.97 eV) was observed for TiO2 with the increase of microwave power. The photocatalytic activity of phenol and congo-red (CR) dyes were investigated using the TiO2 catalyst under visible light irradiation. The results demonstrates that 900 W microwave assisted TiO2 showed superior photocatalytic performance towards CR such as high efficiency (83%) and more stability than other samples. The samples were further characterized by photoluminescence and energy dispersive analysis.