introduce vs introductory

introduce is not an adjective while introductory is an adjective.

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

introduce (adjective)	introductory (adjective)
	serving as a base or starting point
	serving to open or begin
	serving as an introduction or preface

introduce (verb)	introductory (verb)
be a precursor of
place, fit, or thrust (something) into another thing
put before (a body)
cause to come to know personally
furnish with a preface or introduction
bring before the public for the first time, as of an actor, song, etc.
put or introduce into something
bring something new to an environment
bring in or establish in a new place or environment
bring in a new person or object into a familiar environment