A series of cationic half-sandwich cyclopentadienyl-ruthenium(II)-pyridylamine complexes, [(eta(5)-C5H5)Ru(kappa(2)-L)(PPh3)](+) (L = N-amine-substituted pyridylamine ligands) ([Ru]-1-[Ru]-6), along with the analogous cyclopentadienyl-ruthenium(II)-N-isopropylpyr-idylimine complex [(eta(5)-C5H5)Ru(kappa(2)-L)(PPh3)](+) (L = N-isopropylpyr-idylimine) ([Ru]-7), have been synthesized in good yields. Structural identities of all the complexes have been authenticated by H-1,C-13, and P-31 NMR, mass spectrometry, and X-ray crystallography. The synthesized complexes exhibited high catalytic activity for the transformation of the bio-derived furans, 2-furfural (furfural), 5-methyl-2-furfural (5-MF), and 5-hydroxymethyl-2-furfural (5-HMF) to levulinic acid (LA) and the diketones, 3-hydroxyhexane-2,5-dione (3-HHD), 1-hydroxyhexane-2, 5-dione (1-HHD), and hexane-2,5-dione (HD) in water. Efficient transformation of furfural to LA over a range of eta(5)-Cp-Ru-pyridylamine complexes is substantially affected by the N-amine-substituents, where a eta(5)-Cp-Ru-N-propylpyridylamine complex ([Ru]-2) exhibited higher catalytic activity in comparison to other eta(5)-Cp-Ru-pyridylamine and eta(5)-Cp-Ru-pyridylimine complexes. The relative catalytic activity of the studied complexes demonstrated a substantial structure-activity relationship which is governed by the basicity of N-amine, steric hindrance at N-amine, and the hemilabile nature of the coordinated pyridylamine ligands.