Hi Vijay Srinivasan,
Dates cannot be compared with null outside any specific context. Is a given date more or less than null?
Fortunately, you have a specific context in which you need to compare a date with null. That is why you will need to create two IValueConverters for the two columns. One would return DateTime.MinValue when the incoming value is null and the other will return DateTime.MaxValue. Assign these converters to the DataMemberBindings of the two columns. This should solve the problem.
the Telerik team