Graphical Abstract: The complexes of general formula Cu(H2L) (II); [CuLn(L)(NO3)(H2O)n] (where H4L=N,NI-bis[2- hydroxy(3-
carboxynaphtalidene)]ethylenediamine; Ln: Nd, n=6 (III); Eu, n=4 (IV); Gd, n=6 (V) have been synthesized a
nd investigated by different methods (IR spectroscopy, TG analysis and magnetochemistry). The coordination set of complex generators are Cu(N2O2) and Ln(O8-9). The effective magnetic moment values, μeff, at 300 K are: 1.78 (II), 3.22 (III), 6.44 (V) B.M. The temperature dependence (300-2 K) of magnetic susceptibility of [CuNd(L)(NO3)(H2O)6] indicates the antiferromagnetic interaction between metal ions.