In the present study

new series of pyridinium carboxylate protic ionic liquids (PILs) were synthesized by pairing pyridinium cation with carboxylate anion from C

1

-C

3

forming pyridinium formate ([C

5

H

6

N

+

]

[HCOO

-

]

)

pyridinium acetate ([C

5

H

6

N

+

]

[CH

3

COO

-

]

) and pyridinium propionate ([C

5

H

6

N

+

]

[CH

3

CH

2

COO

-

]

) respectively. The physical properties namely

density

viscosity

surface tension (298.15-343.15) K

and refractive index (293.15-323.15) K were measured. Thermal properties namely

glass transition temperature

molar heat capacity

and thermal decomposition temperatures were also determined. The thermal expansivity was calculated using the experimental density data. The effect of increasing the alkyl chain length on the thermophysical properties of the pyridinium carboxylate PILs has been evaluated. As expected the physical properties i.e. density

viscosity

surface tension and refractive index of the investigated pyridinium carboxylates decreased with increasing temperature. In general pyridinium carboxylate PILs possessed low viscosity

high thermal stab

ility and excellent hydrogen bonding capability

and these properties lead them to outperform conventional solvents employed for lignin dissolution.