Channeled Dragonfire

If a card with harmonize is put into your graveyard during your turn, you can cast it if it’s legal to do so before any other player can take any actions.

“Harmonize [cost]” means “You may cast this card from your graveyard by paying [cost] and tapping up to one untapped creature you control rather than paying the spell’s mana cost,” “If you cast this spell using its harmonize ability, its total cost is reduced by an amount of generic mana equal to the tapped creature’s power,” and “If the harmonize cost was paid, exile this card instead of putting it anywhere else any time it would leave the stack.”

You must still follow any timing restrictions and permissions, including those based on the card’s type. For instance, you can cast a sorcery using harmonize only when you could normally cast a sorcery.