Nanospheres with porous cores were prepared from a diblock copolymer poly[(2-cinnamoyloxyethyl methacrylate)-random-(2-(1'-thyminylacetoxyethyl methacrylate)]-block-poly(tert-butyl acrylate), P(CEMA-r-T)-b-PtBA, where the CEMA groups are photo-cross-linkable and the thyminyl groups can H bond with adenine. When mixed with poly [(2-hydrocinnamoyloxyethyl methacrylate)-random-2-(9'adeninylacetoxyethyl methacrylate) or P(hCEMA-r-A), P(CEMA-r-T)-b-PtBA formed micelles in chloroform/ cyclohexane (CHX) with PtBA coronas and cores consisting of P(CEMA-r-T) and P(hCEMA-r-A). Pores were generated after photo-cross-linking the cores and extracting out the porogen P(hCEMA-r-A) with DMF. The presence of pores in the cores of the nanospheres was demonstrated by the much faster uptake of adenine from methanol by the porous nanospheres than the solid nanospheres prepared from P(CEMA-r-T)-b-PtBA without using the porogen. This was also confirmed by the much higher capacity of the porous nanospheres for P(hCEMA-r-A) uptaking.