。
She's rich, but he's poor.
Literal
She [topic-は] rich is [but-が] he [topic-は] poor is.
Two topic-は clauses joined by が ('but') — a textbook contrastive pairing. The dual topic structure highlights the comparison: each person gets their own topic slot, and が draws the line between the two halves. 貧乏 ('poor, impoverished') is a noun (a 漢語 compound: 貧 'poor' + 乏 'lacking'), used predicatively with the copula. Note how this construction uses the conjunctive が rather than けれども or のに — が is the most clinical, fact-stating contrast marker, fitting for a balanced statement of two paralleling facts.