Dexter is an extremely intelligent boy (a self described "Boy Genius") who has been creating fantastic inventions since he was a baby. He considers Albert Einstein to be his greatest influence. He is normally in conflict with his sweet 15-year-old sister Dee Dee. Dexter, though highly intelligent, often fails at what he has set out to do
Dee Dee is Dexter's extremely ditzy, simple-minded, energetic, hyperactive older sister, who inexplicably makes "squishy" sounds with her feet on every step. She usually, in one way or another, sabotages his experiments and destroys the lab every time.
“ the rival ”
Dexter's arch-nemesis. Approximately equal in intelligence to Dexter, he too possesses his own laboratory, which has a very black-and-red color scheme to make it look more evil and may be organic-based. It also is sphere shaped, opposing the design of Dexter's Laboratory.