Two copper(II) coordination compounds with vanillic acid C 8 H 8 O 4 (1), namely [Cu 2 (C 8 H 7 O 4 ) 2 (O 2 CCH 3 ) 2 (CH 3 OH) 2 ] (2) and [Cu 2 (C 8 H 7 O 4 ) 4 (H 2 O) 2 ] (3), were synthesized and characterized. Single crystals of 1–3 were obtained and their crystal structures determined. The structure of 2 shows dinuclear cage structure of copper acetate hydrate type, however with two different carboxylates, acetates and vanillic acid anions, respectively. Both bridging anions are in pairs in trans orientation. Methanol molecules are apically coordinated (Cu–O7 2.160(2) Å), fulfilling square-pyramidal coordination sphere around both copper ions. The compound 2 decomposes outside mother-liquid (yielding [Cu 2 (C 8 H 7 O 4 ) 2 (O 2 CCH 3 ) 2 (H 2 O) 2 ] (2a)) with the removal of methanol, but without significant change of the dicopper tetracarboxylate cage structure, as noticed by μ eff 1.48BM for 2a. Similar was found also in the X-band EPR spectra with three signals H z1 , H ⊥2 and H z2 in the region from 0 to 600mT. The structure of free vanillic acid 1 is composed of dimeric units of two molecules, connected by two parallel hydrogen bonds between carboxylate group of each other (O1–H⋯O2 2.642(3) Å), while the structure of 3 is of [Cu 2 (O 2 CCH 3 ) 4 (H 2 O) 2 ] type. Interestingly, an additional signal in the EPR spectra of 3 is found at 80mT (H ⊥1 ) at 298 and at 116K, next to three signals H z1 , H ⊥2 and H z2 .