There doesn't seem to be.

I only heard if you unlock some class called chemist though not sure if that is what it was called

I think so. Guess I need to be prepped before battle.

This is correct, there is only one class that can use items during battle. The idea behind it was to have magic-based classes able to deal more damage in a short amount of time with the downside being that they eventually run out of MP, whereas physical-based classes typically deal less damage in the same amount of time but can keep going indefinitely.

Refilling MP between battles can be annoying (especially late-game), so I did add the Auto Top Up option that can be used to do so quickly, and it can be favourited for fast access in the Favourites/Quick Menu. This might not always be the best option when money is tighter in the early game, though.