The present work aims to develop a photocatalytic coating for the improvement of indoor air quality. Two types of visible-light responsive photocatalysts (powder and suspension form) were applied into a water-based acrylic coating. The applied materials were characterized and the developed coatings were tested for the pollutant removal efficiency under visible-light irradiation. The coatings containing a stabilized C-TiO2 suspension showed nano-scale and uniform particle distributions. UV treatment was found to be necessary, in order to expose the nano-photocatalytic particle and to promote the NOx removal efficiency under visible light irradiation, from 5 hours (5% de-NOx) to 24 hours (23% de-NOx). In addition, the distribution and the incorporation of the catalyst were significantly improved in case of the coatings incorporating C-TiO2 suspension.