Hi Samir Vaidya,
In 4.x the user controls need to be build in Visual Studio and then registered in the system either by adding them to the toolboxes.config or using the UI - Toolboxes - Page controls - Sections. The approach used in 3.x is not applicable in Sitefinity 4.x.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items