Yes, reference data from an Excel spreadsheet can be imported into Endnote to create separate Endnote records. You will need to add headers at the top of each column in the Excel spreadsheet which correspond to the Endnote generic field names. You may also need to rearrange the Excel columns to correspond to Endnote’s generic field name order. Refer to the Endnote training video “Importing Tab-Delimited Files” and the knowledge base article “Creating a Tab-Delimited Import Format” http://endnote.com/kb/106211
Also suggest using a small subset of Excel records when testing the import process as it’ll facilitate identifying and correcting import issues.