A novel organic-inorganic hybrid cerium-encapsulated selenotungstate comprising three polyoxotungstate building units Na16H6{[Ce3W4O10(H-2 O)(9)(CH3COO)(3)](2)(Se2W7O30)(B-alpha-SeW9O33)(4)}center dot(C5H8NBO3)center dot 119H(2)O (1) was synthesized by the portfolio approach of an in situ self-assembly reaction and step-by-step synthesis. The hybrid polyoxoanion of 1 is constructed from an acetate-coordinated heterometallic {[(Ce3W4O10)(H2O)(9)(CH3COO)(3)](2)(Se2W7O30)}(10+) core encompassing four trilacunary [B-alpha-SeW9O33](8-) subunits. Interestingly, the heterometallic core contains a remarkable [Se2W7O30](10-) building block in which seven W-VI atoms form a W-7 plane and two Se R atoms are situated on two opposite faces of the W-7 plane. In addition, the electrochemical performances of the 1@CFMCN composite (CFMCN: carboxyl-functionalized multiwalled carbon nanotube) were investigated. The 1@CFMCN/GCE (GCE: glass carbon electrode) sensor demonstrates a promising potential in electrochemically sensing dopamine (DPA) or paracetamol (PCM) or even simultaneously detecting DPA and PCM with low limits of 0.053 mu M for DPA and 2.03 mu M for PCM over a wide linear range at high sensitivity.