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The synthesis, crystal structure, spectral characteristics and thermal properties of alkaline-earth metal salts of 4-nitrophenylacetic acid (4-npaH) namely, [Mg(H 2 O) 6 ](4-npa) 2 •4H 2 O (4-npa = 4-nitrophenylacetate) (1), [Ca(H 2 O) 2 (4-npa) 2 ] (2) and [Sr(H 2 O) 3 (4-npa) 2 ]•4.5H 2 O(3) are reported. In 1, the 4-npa ion functions as a charge balancing counter anion for the octahedral [Mg(H 2 O) 6 ] 2+ unit with the Mg(II) ion situated on a centre of inversion. The two unique lattice water molecules link the [Mg(H 2 O) 6 ] 2+ cations and 4-npa anions with the aid of O-H• • • O interactions. Compounds 2 and 3 are one-dimensional (1-D) coordination polymers containing an eight coordinated Ca(II) situated in a general position and a nine coordinated Sr(II) located on a twofold axis. The μ 2-bridging tridentate binding modes of the crystallographically independent 4-npa ligands in 2 and the unique 4-npa ligand in 3 link the bivalent metal ions into an infinite chain with alternating Ca• • • Ca separations of 3.989 and 4.009 Å, respectively, and a single Sr• • • Sr separation of 4.194 Å in the 1-D chain.

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The authors of the title paper (Optik, 125 (2014(Optik, 125 ( ) 1825(Optik, 125 ( -1828 claim to have synthesized a new nonlinear optical (NLO) gamma bis glycinium oxalate (GBGOx) crystal by slow evaporation solution technique. In this communication, many points of criticism, concerning the characterization of this so called GBGOx NLO crystal are highlighted to prove that the title paper is completely erroneous.