li:before{ content: “■”; } How to Encode this Special Character as a Bullit in an Email Stationery?

Never faced this problem before (not worked much on email, I avoid it like the plague) but you could try declaring the bullet with the unicode code point (different notation for CSS than for HTML): content: '\2022'. (you need to use the hex number, not the 8226 decimal one)

Then, in case you use something that picks up those characters and HTML-encodes them into entities (which won’t work for CSS strings), I guess it will ignore that.