[GRAPHICS] A route to porphyrins bearing trans-thiols is described using a thioacetyl containing aldehyde or a thioacetyl containing dipyrromethane in the presence of catalytic BF3. OEt2 followed by oxidation. Metal complexation and ammonium hydroxide induced acetyl removal provides a route to these important molecular systems for future electronics experiments in which the thiols would serve as the adhesion points to gold probes.