basic vs introductory

basic is a noun but introductory is not a noun.

Word	Noun	Adjective	Verb	Adverb
basic	Yes	Yes	No	No
introductory	No	Yes	No	No

As adjectives, basic and introductory are synonyms defined as:

basic (noun)	introductory (noun)
(usually in the plural) a necessary commodity for which demand is constant

basic (adjective)	introductory (adjective)
pertaining to or constituting a base or basis	serving as a base or starting point
of or denoting or of the nature of or containing a base	serving to open or begin
reduced to the simplest and most significant form possible without loss of generality	serving as an introduction or preface
serving as a base or starting point