Hi,
Thank you for your interest in Syncfusion products.
It’s not possible to open more than one document at a time. Since we are using Response it will return after one document is opened or saved. As a workaround we can display each document as link and open the desire document by clicking the links.
Please refers to the below sample:
http://files.syncfusion.com/samples/DocIO.Windows/PDF_Multipledocument_81923.zipFor more samples please refer our Online MVC samples from the below link:
http://samples.syncfusion.com/mvcpdfdemo/v7.2.0.20Please let me know if you have any other questions.
Best Regards,