National Benefactor; son of the National Benefactor Georgios Sinas; Greek Consul in Vienna; Minister to Vienna, Munich and Berlin. He continued and expanded on his father's work in the business sector, and as benefactor. He made major donations to charitable, educational and scientific foundations in Austria, Hungary and Greece (the Amalieion Orphanage, the Eye-Hospital, the Educational Association, the Athens Observatory), and sponsored scholarships for studies in Europe; his scholarship-holders included Konstantinos Sathas, Leonidas Drosis and Nikiforos Lytras.
Sinas' name is mostly connected with the Building of the Academy of Athens. Both for its erection and for its sculptural and painted decoration, Sinas made generous donations from 1856 onwards, and these were continued after his death by his wife Iphigeneia.