Hi Chetan,
Thanks for using Syncfusion products.
We regret to let you know that Syncfusion Controls does not support for toolbox in Visual Studio Express Edition. But you are able to configure the Syncfusion controls manually in VisualStudio toolbox.
Please refer the below link.
http://help.syncfusion.com/ug/common/documents/1012manuallyconfigur.htm
Please let us know, if you have any queries.
Regards,
Sivaguru S