 This was followed in the early 1970s by Princen's prominent role in creating a larger organization, the Indonesian Legal Aid Institute (LBHI), where he rubbed shoulders with many other human rights figures including Adnan Buyung Nasution, Frans Winarta, Besar Mertokusumo, Yap Thiam Hien, Victor D. Sibarani, Mochtar Lubis, Albert Hasibuan and members of the younger generation of activists.The eulogy published after his death by the Indonesian oppositional news and commentary website Laksamana.Net noted that
Princen's work as a lawyer never earned him much in the way of material wealth.Unlike other prominent human rights lawyers whose careers benefited from their high profile on the human rights front, Princen remained a figure whose only interest was in defending the rights of the small.