Sure it would be cool if extraterrestrial life forms were sending us encoded messages. The local chemist might be a little bored though and hiding behind the bushes to make fun of you.

These started looking a little too familiar to be from the stars

When crop circles that are proven or admitted to be created by humans are eliminated, how many of those that remain unexplained actually depict recognizable chemical symbols?

I have no clue about that. I just started browsing a bunch of them and found them familiar. So I put this clip together

Regardless of wether you "beleive" or not, Think about this for a moment.

If a Hypothetical, intelligent (lets assume so as they would have to have built a ship to get here) lifeform wanted to communicate ideas and concepts. Wouldn't they would do so using the universal languages of Maths and Science?

Also wouldn't a molecule of any particular type remain the same no matter what planet it is on/from?

Just some food for thought.

Sure, that's a possibility. Yet you are also making a huge assumption:

You assume that an extraterrestrial mind will come up with the same visual representation of a molecule as us. It's the same as assuming their traffic stop signs will look the same as our traffic stop signs.

Sure the concept of "stop" can be universal but how we depict "stop" with a visual representation is a product of our minds and varies even within earth itself.