Here we have a few sets of codes that you can use to find chemical SMILES strings (structures) if you already know the CAS numbers or the names of your chemicals. Although there are many sources available for us to get SMILES strings, mostly they will not cover all your chemicals if you have a lot. In such cases, checking multiple sources/databases becomes necessary.
This tutorial has also been uploaded in our GitHub page at: https://github.com/Aropha/get-chemical-smiles-by-cas-or-name, where you can also download additional files for your needs.