line of products vs product line

line of products and product line both are nouns.

Word	Noun	Adjective	Verb	Adverb
line of products	Yes	No	No	No
product line	Yes	No	No	No

As nouns, line of products and product line are synonyms defined as:

line of products and product line: a particular kind of product or merchandise

Other synonyms of line of products include business line, line, line of business, line of merchandise.

line of products (noun)	product line (noun)
a particular kind of product or merchandise	a particular kind of product or merchandise