Fluorescent nitrogen-enriched carbon nanodots (C-dots) of 1 to 3 nm were obtained through a one-pot reaction between melamine and glycerol. These C-dots show quantum yields up to 22% and a high two-photon absorption cross-section. The TiO 2 based photoanode sensitized by these C-dots is capable of converting near IR photon energy to photocurrent. The emergence of photoluminescent nanocarbons has attracted significant research interest in recent years, because carbon is cheap, abundant, chemically inert and biocompatible. Carbon nanodots (C-dots) are quasi-spherical particles of finite size, typically less than 5 nm, and comprise either amorphous or graphitic carbon. 1-3 Various works have demonstrated a promising application potential of C-dots in bioimaging, 2,4-7 optoelectronic devices 8 and photocatalysis. 9 A number of methods have been established to synthesize carbon nanodots, from 'top-down' approaches such as arc-discharge, 3 laser ablation, 2 and electrochemical exfoliation 10 to 'bottom-up' syntheses like carrier-supported resol carbonization, 6 dehydration of carbohydrates, 11 thermal oxidation, 12 microwaving 13 and 'hot injection' 14 of carbon precursors. The quantum yields (QYs) of these synthesized C-dots are generally low (typically under 15%). 2,6,13,15-19 While improving synthesis methods towards potential cost-effective mass production is a heated area, various studies have also attempted to unravel the photoluminescence mechanisms of C-dots. The luminescence origin was attributed to a surface trapping effect, 2 and other