Create relationship between 2 spreadsheets

I have a SS named Students, with Student ID#, {LName, FNam}, Grade. The column assignments are: Column A = Student ID#, Column B ={LName, FNam}, Column C =Grade
I want to use this information to populate the second spreadsheet which looks like this:

The second SS is names Skipped and has the same three columns: Student ID#, {LName, FNam}, Grade. The column assignments are: Column A = Student ID#, Column B ={LName, FNam}, Column C =Grade


I have use the following formula in the ID# column to lookup the information in the Student SS:

IF(ISNUMBER(MATCH($B2,Students!C1,0)),INDEX(Students!C2,MATCH($B2,Students!C1,0)),"not found")

However, when I enter a Student ID#, it does not do the lookup and input the name and grade on the Skipped SS.