Solution 1:

NSMutableArray *letterArray = [NSMutableArray array];
NSString *letters = @"ABCDEF𝍱क्";
[letters enumerateSubstringsInRange:NSMakeRange(0, [letters length]) 
                            options:(NSStringEnumerationByComposedCharacterSequences) 
                         usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
    [letterArray addObject:substring];
}];

for (NSString *i in letterArray){
    NSLog(@"%@",i);
}

results in

A
B
C
D
E
F
𝍱
क्

enumerateSubstringsInRange:options:usingBlock: available for iOS 4+ can enumerate a string with different styles. One is called NSStringEnumerationByComposedCharacterSequences, what will enumerate letter by letter but is sensitive to surrogate pairs, base characters plus combining marks, Hangul jamo, and Indic consonant clusters, all referred as Composed Character

Note, that the accepted answer "swallows" 𝍱and breaks क् into and .

Solution 2:

Conversion

NSString * string = @"A B C D E F";
NSArray * array = [string componentsSeparatedByString:@" "];
//Notice that in this case I separated the objects by a space because that's the way they are separated in the string

Logging

NSLog(@"%@", array);

Console

This is what the console returned