Yes, DIMORPHISMS is a Scrabble word!

Letter values in Scrabble US: D 2, I 1, M 3, O 1, R 1, P 3, H 4, I 1, S 1, M 3, S 1.

Is it a valid word?

DIMORPHISMS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

(chemistry) the property of certain substances that enables them to exist in two distinct crystalline forms
(biology) the existence of two forms of individual within the same animal species (independent of sex differences)