I don't have any serious experience in SQL and I even hate to write SQL instead of LINQ. I am happy enough with ORMs.

From the employers and sector view point, is it important to know SQL? Do I have to master on it? Are companies that prefer pure SQL over ORM frameworks a "dinosaur" in the programming world?

Absolutely! SQL is still the lingua franca of databases and although you may do a lot with ORMs you have to understand SQL to understand the decisions ORMs make and the SQL they generate. Also, there are still lots of things that you have to do with custom sql and stored procedures as well. Sorry, no free lunch.