Two new neutral mononuclear Zn(II) and Mn(II) complexes with pyridine-2-amidoxine and carboxylate ligands, [Zn(paH) 2 (OAc) 2 ]Á2CH 3 OH (paH = pyridine-2-amidoxine, HOAc = acetic acid) (1), and [Mn(paH) 2 (OAc) 2 ]ÁC 2 H 5 OHÁ2H 2 O (2), have been prepared and characterized structurally by X-ray crystallography. 1 and free paH exhibit photoluminescence at room temperature in solid state, which is rare so fare for metal complexes with oximebased ligand. The emissions of 1 and free paH arise from the metal-perturbed paH-based p ? p* ligand-to-ligand charge transfer transition (LLCT) and p ? p* charge transfer transition in nature, respectively, in terms of the density functional theory level calculations and molecular orbital analyses.Keywords Zn(II) complex Á Mn(II) complex Á Synthesis Á Crystal structure Á Photoluminescence Á Theoretical calculation Á Electronic structure Á The density functional theory Coordination chemistry of oxime-based ligands has been extensively studied owing to the fact that they are usually bidentate or multidentate, thus may bridge metal ions. On the other hand, their metal complexes have been found to be very important so far, as they have a wide range of applications in technology, medicine, and agriculture [1]. As a result, a series of bidentate or multidentate oximederived ligands have been synthesized and employed in fabricating mononuclear or multi-nuclear metal complexes [2][3][4]. For example, the oxime-hydroxy ligands were famous in forming magnetic multi-nuclear metal complexes [5]. However, though the pyridine-2-amidoxine ligands could coordinate metal ions and generate stable complexes through the oxime groups [6-8], the introduction of N-donor from the pyridine groups could also result the variation of coordinative mode. Therefore, it is valuable to investigate the coordination chemistry of this ligand.Neutral oligomeric photoluminescent and/or electroluminescent metal complexes are a fascinating class of molecules that have been found applications in many areas such as light emitting device (LED) [9][10][11][12]. Among them, Zn(II) chelate complexes have been focused due to their excellent performance in photoluminescence and/or electroluminescence, since the first report of a double-layer green organic electroluminescence device in 1987. To the best of our knowledge, however, no investigations have been carried out on the photoluminescence and/or electroluminescence of Zn(II) and other metal complexes with oxime-based ligands even though a growing number of complexes have been reported with novel structures [13][14][15][16]. Herein, we report the syntheses, structures, photoluminescence, and theoretical investigation on their photoluminescent property for two new neutral mononuclear metal complexes with a oximebased ligand, pyridine-2-amidoxine, namely [Zn(paH) 2 (OAc) 2 ]Á2CH 3 OH (paH = pyridine-2-amidoxine) (1) and [Mn(paH) 2 (OAc) 2 ]ÁC 2 H 5 OHÁ2H 2 O (2) [17]. The synthesis of paH was carried out according to literature [17]. The synthesis of 1: to a solution of pa...