Amphiphilic zinc porphyrin (P-zn; electron donor, D)-fullerene (C-60; electron acceptor, A) dyads 2 nand 3, bearing an identical hydrophilic wedge with triethylene glycol chains but different linkers between the P-Zn and C-60 units, self-assemble into nanotubes with essentially different dimensional and geometrical features from one another. The nanotube from dyad 2 with an ester linker consists of a bilayer wall formed with coaxially segregated D and A nanodomains along the tube axis (coaxial D-A heterojunction), thereby displaying explicit photoconductivity with ambipolar carrier transport properties. In contrast, the nanotube from dyad 3 with a rigid arylacetylene linker consists of a monolayer wall with an alternate geometry of D/A stacking, resulting in poor photoconducting outputs. Such a geometrical difference also significantly affects the photovoltaic properties.