Recent molecular based compounds demonstrate various kinds of physical properties based on peculiar crystal, molecular and electronic structures. Sometimes these systems require specific measurements due to quite small sample amount, special treatment at extreme conditions or other difficulty. In our studies, we have developed novel heat capacity measurement systems and established novel technique to investigate dielectric and electrostrictive characters. In the thermodynamic studies on the spin liquid states of organic dimer-Mott insulating systems, we have found the close relation between the spin entropy represented by T-linear coefficient γ and the magnetic interaction in molecular based quantum spin liquid systems. In the study of novel type system of Non-Coulombic-Ionic Solid, we have found the remarkable value of the dielectric constant and high ion conductivity.