In the past decade, the search for visible-light photocatalysts that are highly active under visible light irradiation has been a hot race worldwide. This is mainly due to the great significance of such photocatalysts in clean energy and environmental applications such as alternative solar cells, water splitting for hydrogen production and photochemical degradation of pollutants in water and air. Nanocrystalline titania has been widely investigated due to its low cost, non-toxicity and potential in numerous applications. To overcome the limitation of UV-only photocatalytic activity of titania, nearly all possible and known strategies including dye-sensitization, non-stoichiometric modification of TiOx, coupling with other narrow band-gap semiconductors, transition metal and nonmetal doping have been attempted. Among these strategies, non-metal doping has shown a great potential in increasing visible-light photocatalytic activity. Recently, we have developed modified mesoporous nanocrystalline titania by iodine, nitrogen and also the combination of boron and nitrogen, respectively, as highly efficient visible light photocatalysts. These photocatalysts exhibited excellent visible light photocatalytic activity in degradation of organic pollutants. Detailed photoelectrochemical study and the first principle calculations on these photocatalysts led to better understanding of the relationships among material synthesis, structural modification and photocatalytic performance, which can shed light on the rational design of efficient visible light photocatalysts.