Instant JChem databases are only available for import if the Instant JChem application and the JChem4XCL integration are running. This is described in the Instant Jchem User Guide in detail, but the most important steps are mentioned here as well.
{primary} Please note that the Import IJC feature is deprecated since version 21.4. You can read more about how to use it with versons before 21.4 here.
Start Instant JChem and click the Projects label on the left side.
Select an ijc-project and right-click it.
Click the Start JChem4XCL integration button.
JChem for Excel communicates through web requests with the Instant JChem application.
The information including chemical structures is collected into OData objects and sent in XML files.