Sending Mail via SMTP in C# using BCC without TO

Do the same thing you do for internal mail blasts where you don't want people to reply-to-all all the time.

Send it to yourself (or a dummy account), then add your BCC list.

I think if you comment out the whole emailMessage.To.Add(sendTo); line , it will send the email with To field empty.

You have to include a TO address. Just send it to a "junk" email address that you don't mind getting mail on.