Disclosed herein are novel dicationic teraryl compounds and their aza analogues, including compounds of Formula (IIe): wherein p and q are each 0 and each A, Y and Z is CR4. An exemplary compound of Formula (IIe) is: Methods for combating microbial infections, such as parasitic Leishmania species, with novel dicationic terphenyl compounds and their aza analogues are included. Processes for synthesizing novel dicationic terphenyl compounds and their aza analogues are disclosed along with methods for evaluation of the compounds as potential anti-protozoan agents.