This work compares the self-assembly of nanometer-sized amphiphilic Janus-type and patched polyphenylene dendrimers (PPDs) in solvent/non-solvent mixtures utilizing static and dynamic light-scattering measurements. First- and second-generation (G1 and G2) dendrimers are functionalized with substituents of different polarity, i.e., polar neo-pentyl sulfonate or sulfonic acid groups are combined with non-polar propyl groups. Neo-pentyl sulfonate PPDs give rise to defined supramolecular assembly structures, irrespective of their amphiphilic surface functionalization or size. In contrast, the self-assembly of PPDs with sulfonic acid substitution exhibits a pronounced dependence upon substitution pattern and generation. In particular, the Janus dendrimers demonstrate an increased tendency toward self-assembly compared to their patched counterparts. This trend is more pronounced for G2 than for G1 PPDs.