Interweave Spell
Level 14 Metamagic Sorcerer

Prerequisites: dispel magic in your spell repertoire

You weave dispelling energy into a spell, sending both effects at a foe. If your next action is to cast a single-target spell against a creature, and you either hit the foe with the spell attack roll or the foe fails its saving throw, you can cast dispel magic on the foe as a free action, expending a spell slot as normal and targeting one spell effect affecting the foe.