Abstract Ten new complexes are reported: Cu(MBEn) 2(NO 2) 2, Cu(DBEn) 2(NO 2) 2·3H 2O, Cu(DBEn) 2 (NO 2) 2·H 2O, CuMe 4En(NO 2) 2, CuEt 4En(NO 2) 2, CuMe 2DBEn(NO 2) 2, Ni(MBEn) 2(NO 2) 2, Ni(DBEn) 2(NO 2) 2, NiEt 4En(NO 2) 2 and NiMe 2DBEn(NO 2) 2 (MBEn = N-benzylethylenediamine; DBEn = N,N′-dibenzylethylenediamine; Me 2DBEn = N,N′-dimethyl-N,N′-dibenzylethylenediamine; Me 4En = N,N,N′,N′-tetramethylethylenediamine: Et 4En = N,N,N′,N′-tetraethylethylenediamine.) All are magnetically normal high-spin complexes. The nitrite groups are chelated, asymmetrically in copper and symmetrically in the nickel complexes of Me 4En, Et 4En and Me 2DBEn. Ni(DBEn) 2(NO 2) 2, a nitrito complex in the solid phase, exists in a nitro-nitrito equilibrium in chloroform. The solid trihydrate nitrito complex, Cu(DBEn) 2(ONO) 2·3H 2O on heating at 110°C gave Cu(DBEn) 2(NO 2) 2·H 2O, a nitro-nitrito isomeric mixture. The nitrite groups are coordinated through N in Mi(MBEn) 2(NO 2) 2 and O in Cu(MBEn) 2(ONO) 2. It is suggested that steric factors as well as the nature of the metal ion play an important part in the mode of nitrite coordination.