So often we see whereas and although incorrectly punctuated with a semicolon in front and a comma after as in
…was seen with him; although, she did not…
…was seen with him; whereas, she did not….
This punctuation implies that these words are conjunctions (conjunctive adverbs) that start a new sentence. Instead, whereas and although are conjunctions (subordinate conjunctions) that start dependent clauses. When these two words begin a clause that is at the end of a sentence, there is generally no punctuation in front of them.
…I spent no time with her whereas my brother never left her side.
…I spent no time with her although my brother never left her side.
A reporter sent this sentence, which is correctly punctuated here:
…If you look at Picture 24, it looks like my mom or somebody else, a third person, was on the boat taking Picture 24 whereas Picture 28 that you referred to has just the two of us on it.
When the clause begins the sentence, of course, there is a comma after it.
…Whereas he is an exemplary student, he will…
…Although he is an exemplary student, he will…
There are some other issues with these two words, but these are the basics.