Abstract: Compounds suitable for NMR imaging having the formula: ##STR1## wherein a is 2 or 3;b is an integer from 0 to 4;Me.sup.(a+) is Fe.sup.(2+), Fe.sup.(3+), Gd.sup.(3+), or Mn.sup.(2+) ;E.sup.(b+) is an ion of an alkali metal, alkaline earth metal, alkyl ammonium, alkanol ammonium, polyhydroxyalkyl ammonium, or basic protonated amino acid, said ions representing a total charge of b;m is an integer from 1 to 5;R is H, alkyl with from 1 to 8 carbon atoms, alkyl with from 1 to 8 carbon atoms wherein from 1 to 5 carbons are substituted with OH; aralkyl with 1 to 4 aliphatic carbon atoms; phenyl or phenyl substituted by halogen, hydroxyl, carboxyl, carboxamide, ester, SO.sub.3 H, sulfonamide, lower alkyl, lower hydroxy alkyl, amino, acylamino; (poly)oxa-alkyl with 1 to 50 oxygen atoms and from 3 to 150 carbon atoms, wherein 1 to 5 hydrogen atoms may be substituted by OH;R.sub.1 is the same as R.sub.2 oris --CH.sub.2 COOZ, --CH(CH.sub.3)COOZ, CH.sub.2 CH.sub.2 --N(CH.sub.2 COOZ).sub.