St. Dimitrios (formerly St. Mark's)

As early as 1963, the development plan for the "New Town" envisaged in the Chorweiler borough reserved a plot for a Catholic church. From 1967 the mother parish of Christi Verklärung commissioned Schaller to draw up preliminary plans for a branch church seating 250, complemented by a sacristy, a multipurpose room and a kindergarten. While the congregation initially received Schaller's early-1968 designs with scepticism, the archdiocese's art commission approved them in January 1969.

Ground was broken on 25 April 1971, and the topping-out ceremony and the laying of the foundation stone coincided on 20 and 21 May 1972. After a blessing by Prelate Josef Pock, the church came into use from May 1973, though its formal consecration did not follow until 16 January 1984. In late 1996 the parish leased the building for 25 years to the Rum Orthodox congregation of St. Dimitrios. Following a fire in 2000 the church was refurbished and reshaped into a purely Orthodox place of worship, which the congregation finally purchased in May 2001. A Catholic Mass is still celebrated there once a week.

Schaller himself designed the basic elements for the altar, ambo, tabernacle and font, which were realised by Paul Nagel. The tabernacle, whose sacrament house was a finial from Cologne Cathedral, moved after the 2007 sale to the church of Christi Verklärung in Heimersdorf. An outdoor sculpture in the form of a lion of St. Mark is the work of Jochem Pechau. In 2004 the congregation installed an iconostasis crafted in Homs, Syria.