Pure cellulose has been successfully isolated from tomato peels by either acidified sodium chlorite or chlorine-free alkaline peroxide routes, at 10.2–13.1% yields. Negatively charged (ζ=−52.4mV, 0.48at% S content) and flat spindle shaped (41:2:1 length:width:thickness) cellulose nanocrystals (CNCs) were isolated at a 15.7% yield via sulfuric acid hydrolysis (64% H2SO4, 8.75mL/g, 45°C, 30min). CNCs could be facilely assembled from dilute aqueous suspensions into highly crystalline (80.8%) cellulose Iβ fibrous mass containing mostly sub-micron fibers (ϕ=260nm) and few interconnected nanofibers (ϕ=38nm), with 21.7m2/g specific surface and 0.049m3/g pore volume. More uniformly nanofibers with average 42nm width and significantly improved specific surface area (101.8m2/g), mesoporosity and pore volume (0.4m3/g) could be assembled from CNCs in 1:1 v/v tert-butanol/water mixture.