line of products vs business line

line of products and business line both are nouns.

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

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

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

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

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