Strings does not have fonts.
You need to set the font of the label itself, or use Attributed strings
Here is a simple example of how to use more than one attribute in an attributed string:
NSString *s1 = @"Hello ";
NSString *s2 = @"World";
NSDictionary *attr1 = [NSDictionary dictionaryWithObjectsAndKeys:
[UIFont fontWithName:@"Arial" size:20] , NSFontAttributeName, nil];
NSDictionary *attr2 = [NSDictionary dictionaryWithObjectsAndKeys:
[UIFont fontWithName:@"Georgia" size:40] , NSFontAttributeName, nil];
NSMutableAttributedString *as = [[NSMutableAttributedString alloc]
initWithString:[s1 stringByAppendingString:s2] attributes:attr1];
[as setAttributes:attr2 range:NSMakeRange(s1.length, s2.length)];
To put the text in a label you can use:
myLabel.attributedText = as;
I would advice against putting this kind of formatting in macros, as the code becomes messy and harder to maintain.