I'm putting this here because, honestly, I have no idea what to do with this question.

 

 

So, when you write a chord progression, you might substitute a major chord for its relative minor (a minor chord whose root is two notes below the substituted major chord) or, for that matter, a minor chord can be substituted with a major chord by reversing the process.

 

 

But could you substitute either with a relative diminished chord one note below/above for major and minor respectively? It sounds like it could make sense, but of course you'd get a very peculiar sound.

i don't see why you coudln't. Music is not limited, if you want to write something that sounds weird, do it!

Well, yeah, I mean, you obviously could do it, but would it work harmonically?

It's really your own appreciation that matter here, dissonant chord is acceptable if they're wanted by the author. Harmonically, it might seems a bit odd at first but if the full progression is the same as a major or minor (same intervals) it should seems right.