Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<AnonymousType#1>' to 'System.Collections.Generic.List<string>

I have the code below:

List<string> aa = (from char c in source
                   select new { Data = c.ToString() }).ToList();

But what about

List<string> aa = (from char c1 in source
                   from char c2 in source
                   select new { Data = string.Concat(c1, ".", c2)).ToList<string>();

While compile getting error

Cannot implicitly convert type 'System.Collections.Generic.List<AnonymousType#1>' to 'System.Collections.Generic.List<string>'

Need help.