Need some expert assistance. Have two Excel spreadsheets, sheet 1 & sheet 2 both with 1,000 rows. Both spreadsheets have common columns C [client name] and H [email address].

Task: need formula for cells H4:H1000 spreadsheet1, if column H in spreadsheet 1 is blank, then insert any data contained in spreadsheet 2 column H. Otherwise, leave spreadsheet 1 column H blank. Below are my two unsuccessful attempts:

=INDEX('[Sheet2]'!$H$4:$H$519,AND(MATCH(C4,'[Sheet2]'!$C$4:$C$519,0), '[Sheet2]'!$H$4:$H$519=””))

=IF('[Sheet2]'!$H$4:$H$519=””,INDEX('[Sheet2]'!$H$4:$H$519,MATCH(C4,'[Sheet2]'!$C$4:$C$519,0)))

Both return #NAME errors. Any suggestions, anyone? Thank you in advance for your most prompt response.