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 (H2-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. © 2013 Elsevier B.V. All rights reserved.