The first class of square-planar Pt(II) complexes bearing electron-poor alkenes, i,e., [PtMe(N,N-chelate)(eta(2)-CH2=CHCOR)]BF4 (R = H, NMe2, Me, OMe), is described. By using N,N ligands with suitable steric properties, it was possible to inhibit olefin dynamic processes in solution, thus allowing a thorough characterization of the complexes. Insertion of methyl acrylate into the Pt-Me bond provides a rare example of migratory insertion of an alkene into a Pt-alkyl bond.