Eleven of them were awarded life imprisonment and another three years imprisonment by a Special Additional Sessions Court at Kozhikode last month.
The accused contended that there was no evidence to implicate them in the case.
Some of the witnesses were RSS and RMP activists, they contended.
The appeal is likely to come up before the division bench on February 24.
Chandrasekharan, a former CPI(M) wholetimer from the red bastion Onjiyam near Vatakara in north Kerala, was hacked to death by an eight-member gang on May 4, 2012.