Magnetic studies. Magnetic measurements were performed on 1 in the temperature range of 1.9-300 K under an applied DC field of 1000 and 10000 Oe to determine the thermal dependence of the T ( is the is magnetic susceptibility equal to M/H per [CrMn1.5] unit) as a function of temperature (Figure , left). At 300 K, the measured T value is 5.89 cm 3 mol -1 K, which is lower than the spin-only T value of 8.437 cm 3 mol -1 K (g= 2.0) that is expected for one [CrMn1.5] unit with Cr(III) ion having t2g 3 eg 0 electronic configuration with S=3/2 and Mn(II) ions having t2g 3 eg 2 electronic configuration with S=5/2. This suggests dominant antiferromagnetic exchange in 1, which is also evident from further decrease of the T value on lowering the temperature down 60 K where T reaches a value of 4.57 cm 3 mol -1 K. Below this temperature, the T vs. T plot shows a strong field dependence which is predicted for systems having large magnetic moment, exhibiting rapid saturation of magnetic moment at low temperatures. Upon further cooling, the T value starts increasing smoothly till it reaches a maximum value of 49.72 cm 3 mol -1 K at 4.75 K, due to topology of AF exchange within 1D chains. After this, the T value decreases to reach a final value of 26.29 cm 3 mol -1 K at 1.9 K indicating saturation of the magnetic moment at low temperatures. The Curie-Weiss fit for the magnetic moments also gives a  CW of -26 K which signifies the antiferromagnetic interactions present in the system (Figure , right).