Ecamsule is interesting but unfortunately only blocks a very narrow wavelength of UVA, which means it has to be mixed with other chemicals which are usually the benzene derivatives I mention. It's also water-soluble so very difficult to make it waterproof.

Materials science is hard, and it's even harder when it comes to things we put in and on our bodies, which is why we shouldn't sensationalize the benefits of new chemicals without acknowledging their downsides, especially when we have found something that works exceptionally well, is cheap, and is merely cosmetically challenging (zinc oxide).