The present invention relates to small cationic ortho-5,15-di-heteroaryl
porphyrin derivatives, in particular porphyrins, chlorins or bacteriochlorin of formula (I) or pharmaceutically acceptable salts thereof.This invention also relates to the use of the above-mentioned cationic ortho-5,10-di-heteroaryl
porphyrin derivatives of Formula (I) or a pharmaceutically acceptable salts thereof, in photodynamic inactivation of microorganisms, where the referred derivatives are able to treat the same in the presence of an adequate light.The present invention also describes pharmaceutical compositions comprising one or more of the cationic ortho-5,10-di-heteroaryl
porphyrin derivatives, in particular prophyrins, chlorins or bacteriochlorins of Formula (I), or pharmaceutically acceptable salts thereof, for the treatment of bacterial and / or fungi and / or yeasts and / or viral infections, in humans or animals.