Studied here are thin films of a series of phenyl-porphyrins. The effect of the phenyl number and positioning on the porphyrin core is shown to have a significant impact on the ability of phenyl-porphyrins to produce aggregates. When four phenyl groups (H2TPP) and three phenyl groups are present (H-2-Tri-PP) a strong aggregate film forms with fractal like structure. When two phenyl groups are present little evidence for aggregation can be determined, however fractal structure persists. (C) 2013 Elsevier B.V. All rights reserved.