Google Apps Script for Gmail, creates a label that matches all threads where you are the last sender. Useful for finding email messages in your mailbox that are still awaiting a response from the customer. Credit @GSAPU.
function label_last_sent_message() { var emailAddress = Session.getEffectiveUser().getEmail(); Logger.log(emailAddress); var EMAIL_REGEX = /[a-zA-Z0-9\._\-]+@[a-zA-Z0-9\.\-]+\.[a-z\.A-Z]+/g; var label = GmailApp.createLabel("LastSentMessage"); var d = new Date(); d.setDate(d.getDate() - 7); var dateString = d.getFullYear() + "/" + (d.getMonth() + 1) + "/" + d.getDate(); threads = GmailApp.search("in:Sent after:" + dateString); for (var i = 0; i < threads.length; i++) { var thread = threads[i]; var lastMessage = thread.getMessages()[thread.getMessageCount()-1]; var lastMessageSender = lastMessage.getFrom().match(EMAIL_REGEX)[0]; if ((thread.getMessageCount() > 1) && (lastMessageSender == emailAddress)) { thread.addLabel(label); } } }