Match formula Excel case sensitive
Solution 1:
Try:
=IF(ISERROR(MATCH(TRUE, EXACT(A2,Dictionary!$A$1:$A$2800),0)), 0, 1)
It's a trick that's explained here:
http://instantefficiency.wordpress.com/2013/01/04/case-sensitive-match-function-in-excel/
EDIT
NB: This is an array formula, so you have to press Control+Shift+Enter after entering it in Excel.