Is there any way in which I can include structures of molecules (line diagrams) in the question? It would be helpful to clarify the question to a greater extent.
I usually use ChemDoodle
There is a plan in the pipeline to integrate ChemDoodle into the editor, but I don't have the time to get working on that right now.
Most of my answers concerning organic chemistry contain a structure or two ;-)
I use BKChem under GNU/Linux, installed from a repo. I save the sketches as SVG and export them to transparent PNG for upload.
There seem to be tarballs and installers for Windows and Mac OS too, but I haven't tried those - personally I'm not interested in these platforms.