The molar heat capacity at constant pressure of the ternary chalcopyrites LiInSe2 and CuInSe2 have been determined at temperatures from 2K to 300 K with an adiabatic microcalorimeter. From the low temperature data we derive the following Debye temperatures at 0 K : theta(0)(LiInSe2) = 265 (10) K and theta(0)(CuInSe2) = 228(3) K. The standard entropies and enthalpies at 298.15 K are calculated by integration of the specific heat curves : S-0 = 146.6(1.5) J (mol K)(-1) and H-H-0 = 20.17(0.3) J K-1 for LiInSe2, and S-0 = 158.2(1.6) J (molK)(-1) and H-H-0 = 21.32(0.25) J mol(-1) for CuInSe2. Comparisons are made with previously reported values for the molar heat capaciy of these compounds, measured above 200 K, and with other chalcogenides of the type A(I)B(III)C(2)(VI), with A = Cu, Ag, B = Ga, In and C = S, Se, Te. It is shown that the averaged atomic heat scales to one general curve within 3% for ail known chalcogenide compounds except the Li compounds. LiInSe, displays an excess heat below about 80K that is represented by a (two-level) Schottky anomaly with an energy splitting of Delta/k = 71.4(4) K suggesting that the Li atom could reside in a double-well potential. Inspection of previously reported data for LiInTe2 hint at a similar effect in that compound.