A very simple facile method of preparation of carbon dots, by acid assisted ultrasonic chemical method has been demonstrated. Dextrose can be efficiently and simply synthesised into water-soluble photoluminescent carbon dot (CDs). The HRTEM confirms its size less than 15nm and its amorphous nature. We have tried to emphasized that even amorphous carbon dot has its own importance in the advance materials world by combinedly showing different possible applications of amorphous carbon dots. CDs were used in making fluorescent ink, flexible film and in sensing picric acid (TNP). The presence of surface states was shown by FTIR spectroscopy. The UV-Vis absorption spectra demonstrate the n-π∗ transition and the π-π∗ transition. The emission peak of PL spectra is near blue luminescent region. Significant changes were observed in the UV-Vis and PL spectra of CDs in the presence of TNP (Tri-Nitro phenol). The synthesized CDs has been showed as a source for direct applications in sensing explosives, as an invisible ink and as a flexible photo luminescent thin film.