1. Both authors are part of the Dark Romantics from American Literature. As such, they viewed human nature as inherently evil and created characters who either give in to the "darkness" of their souls (such as Chillingworth and Dimmesdale in The Scarlet Letter) or commit evil deeds simply because their hearts are "wicked" (the narrator of "The Tell-Tale Heart," or Rappaccini in Hawthorne's "Rappaccini's Daughter").
2. Both authors rely on complex syntax and detailed imagery. Hawthorne's short stories and novels contain numerous descriptive passages filled with lengthy and varied sentence structure. Poe's short stories not only demonstrate unusual and complicated syntax, but they also exemplify the formal, elaborate diction of Romanticism.
1. Even though Hawthorne did write some tales with Gothic elements, he does not rely on the Gothic style that Poe is a master of.
2. Poe created the modern detective story (a story in which an intelligent civilian outsmarts the police and solves a case through imagination and logic). Hawthorne stays close to his Romantic roots and chooses to set some of his stories and novels in the earlier days of America.