I've checked the official website of the developers and it appears that OpenChem Pro is an application unavailable for public testing (trials). There is brief information about it, but that's it. No other thing is available related to downloading, registration, buying options, etc. You will have to contact the official developers in order to obtain additional details about the possibility to test it. The chances also increase if you are an employee in a University.
- Contact email: firstname.lastname@example.org