Is a molecule of naphthalene macroscopic or tiny?

Very tiny: Virtually all molecules are very tiny, including napthalene. The only molecules close to being macroscopic are some larger dna molecules and some synthetic polymers. Most molecules can not even be seen with strong microscopes, though electron microscopes can see large molecules.

Microscopic: Molecules can not be seen with the naked eye. A special kind of ultra powerful microscope is needed to magnify molecules several million times before they can be seen.