A series of novel tetra-meso-thien-2-yl porphyrins were synthesised, and the effect of the variation in the thienyl group on the photophysical properties were studied. Ground and excited state UV–vis absorption, steady-state and time-resolved emission, resonance Raman spectroscopy, and cyclic voltammetry, were used to establish the extent of electronic communication between the central Zn(II) porphyrin ring and the various meso-substituent groups. The properties of these novel thienyl porphyrins were compared to zinc tetraphenylporphyrin (ZnTPP), to elucidate the effect of the position and number of thienyl rings. The photochemically-driven antimicrobial activity of zinc(II)-5,10,15,20-tetra(thien-2′ -yl)porphyrin (ZnThPP) as a coating, was established against both Gram-positive and Gram-negative bacteria, and compared to ZnTPP. Visible irradiation of the porphyrins results in a significant antimicrobial response.