Like hand-written text recognition, hand-drawn chemical structure recognition can be categorised into online and offline recognition tasks . Online chemical structure detection primarily denotes converting a chemical structure drawn on a digital medium, such as a tablet or personal computer, into a machine-readable format in real time. If the detection is inaccurate, the user can adjust their drawing style to make the system predict the molecule correctly. In contrast, offline chemical structure detection predominantly deals with previously drawn chemical structure images. These images exhibit a wide array of drawing styles, making it considerably more challenging to recognise them with high confidence .