The Bandoneon was named after instrument dealer Heinrich Band in the 1850s and is based on the Chemnitzer concertina (a large square concertina physically distinct from Wheatstone's model). It is most well known today for playing Tango music in Argentina.
The Bandoneon is fully capable of playing chromatic melodies and the long bellows can be bounced off the knee for sharp accents. Multiple buttons can be pressed for chords.
The instrument was championed by Argentinian composer Astor Piazolla who created some intricate modern tango inspired music for the concert hall.