Answer:
No. In the words City Science Center, city and science are both nouns being used as adjectives. The word center is the main noun. If you were to say:
"The city science center is cool." you could see that center is both the simple predicate and the subject noun.
City Science Center is a proper noun.
Pronouns are words: I, you, he, she, we, us, you all, they, it, etc.
Pronouns are use in the place of nouns.
Proper nouns gives the names of people, places and things.
For ex:
John went to the movies with Zoey. John and Zoey had an amazing time.
instead of using John and Zoey's name twice you could say:
John went to the movies with Zoey. They had an amazing time.