Python, pandas

Let say i have my dataframe df and i want to create a dictionary mydict where I set the values in column col$2$ as the keys for values in column col$1.$ Im used to use the following code for it:

mydict $=$df$.$set$\_$index$(\text{'}$col$1\text{'})[\text{'}$col$2\text{'}].$to$\_$dict$()$

Now, how do i need to modify my code to make my dictionary case insensitive?