[ente]

ok well i dont think they work or worked together... why?

well because aizens goals are pure selfish so there is no place for a partner....
for urahara its hard to say i dont think he did those research on rukongai citizens (remember the part where someone says it wont work on ordinary souls i think it was aizen thats why he tested it(the substance) on stronger souls) urahra wouldnt use his research in such a way ofc hes a scientist but i doubt he uses such ways (he tested his bankai puppet thing on his own too not with someone else)

aizen said 'you're just the man I thought you were, I'm glad you came here tonight' because he is really glad urahara is here.. urahara is his hope, aizen was unable to create a hybrid by now but this substance he most likely stole from urahara worked pretty well and he hopes that urahara reveals a ways to save shinji and the others (--->hogyouku)