• We have prepared Undoped and N-doped C-dots from Opuntia ficus Indica plant extract. • The synthesized Undoped and N-doped C-dots exhibit, the green fluorescence. • We found higher photocatalytic activity in N-doped C-dots than Undoped C-dots. • N-doped C-dots have utilized as photocatalytic for the degradation of Methyl orange dye. • Further we have study them anti-bacterial activity using gram negative and gram positive bacterias. A carbon dot is an attractive material for the photocatalytic degradation of organic pollutant. Moreover it’s extensively used as a material to control the growth of micro organisms. Herein we are reporting the synthesis of Undoped and N-doped carbon dots (N-CDs) derived from Opuntia Ficus Indica (O.F.Indica) fruits. Further we have well characterized by UV-Vis, FT-IR, XPS spectral, HR-TEM, Raman and XRD techniques. The synthesized Undoped and N-CDs are stable for 3 months. Finally we have found the N-CDs shows the higher photocatalytic activity then Undoped C-dots, due to presence of N-atom. We also have discussed the possible degradation mechanism of Methyl Orange (MO). Finally the N-CDs was utilized their antibacterial activities. We used Streptococcus Pyogenes, Staphylococcus Aureus , Klebsiella Pneumoniae, and Shigella Flexneri. Among them we found Streptococcus Pyogenes a bacterium was largely controlled the growth by our N-CDs.