We propose a strategy utilizing carbon nanotube (CNT) agglomerates in solution, typically undesired precipitates from dispersions of isolated CNTs, for fabricating advanced composites. Importantly, long, single-walled carbon nanotubes (SWNTs) were necessary to make highly concentrated (above 3.0 wt%) and very stable CNT suspensions. SWNTs in the agglomerates formed a dendritic network similar to venation and vein patterns observed in nature. Through this strategy, we demonstrated a 10-fold increase in electrical conductivity of a rubber-composite. Our results showed that the two CNT dispersion strategies, i.e., isolated CNTs, and dendritic CNT agglomerates are complementary, and each demonstrated distinct advantages and disadvantages, and their application is intended toward different uses; our results show the individual values of each approach.