In this study, a SiO2@carbon dot (CD) nanohybrid was prepared by a hydrothermal method and incorporated into waterborne polyester matrix through an in situ process to develop the polyester nanocomposite. The nanohybrid possesses a specific surface area of 348.67 m(2)/g and pore volume of 0.927 cc/g. The nanocomposite exhibited a wavelength-dependent photoluminescence property. The thermosetting nanocomposite showed enrichment in tensile strength (7.8-39.2 MPa), elongation at break (245-294%), scratch hardness (>10 kg) toughness (17.18-65.0 MJ/m(3)), and impact resistance (>8.9 kJ/m(1)) as well as in thermal degradation temperature. The contact angle of the nanocomposite surface varied from 103.9 degrees to 106.3 degrees, which confirmed the formation of hydrophobic surfaces. The nanocomposite exhibited excellent photocatalytic activity against organic pollutants and biodegradability on exposure to Pseudomonas aeruginosa. Further, simple physical mixing of Rhodamine B with the nanohybrid and the nanocomposite in water emitted white light on longer exposure to UV light. Thus, this environmentally benign polyester/SiO2@CD-based nanocomposite could be used as a multifaceted material.