The style of the facade is a testimony to the affection that pope Alessandro VII Chigi had towards the Church of Saint Raimondo al Refugio, which he sponsored.
A special space in front of the Church was created for a better appreciation of the new front. This allowed Siena to adopt the concept of scenic design in city planning, which was already very successful in Rome. The Chigi coat of arms stands out against the marble facade, which according to a number of sources was worked upon by the Sienese architect Benedetto Giovannelli, reportedly finishing the facade by 1660.

Even though the Church's vault was damaged during an earthquake in 1798, the priceless collection of Sienese art from the first two decades of the 17th Century was unharmed, and remains well-preserved inside the Church. The main set of paintings is made up of three large altarpieces, alongside a set of smaller paintings done under the patronage of Aurelio Chigi. After Chigi's Death, in 1610, his Brother, Agostino, head of the Spedale Santa Maria della Scala, ensured that the remaining paintings were finished. The iconographic complex is made up of representations of the stories of Saint Galgano, Saint Catherine and Saint Raimondo di Pennafort. Moreover, it bears witness to the religious zeal that pervaded Siena during the era of the Catholic reformation. On the left wall is San Michele Arcangelo appare a San Galgano by Rutilio Manetti, dating back to 1613. Next to Manetti’s work is an altarpiece representing the Morte di San Galgano, which was presumably painted by Ventura Salimbeni and Francesco Vanni. The painting cycle continues with I Parenti tentano di distogliere San Galgano dalla vita eremitica, another work of Rutilio Manetti dating back to 1613. The work at the end of the left wall depicts the miracle of San Raimondo che cammina sulle acque, attributed to Stefano Volpi. On the left of the main altar is the Adorazione ai Magi, followed by the large altarpiece of Natività con gli angeli  started by Alessandro Casolani and finished, after his death, by Francesco Vanni. On the right side of the altar, on the back wall, is the Circoncisione di Gesù  by Giovanni Battista Giustammiani, also known as il Francesino.
Moving on to the right wall, a painting by Francesco Rustici, also known as il Rustichino, depicts a miracle by the Saint after which the Church was named: San Raimondo resuscita un fanciullo. Next to it,Gesù restituisce l’abito del povero a Santa Caterina by Sebastiamo Folli; and the large altarpiece depicting Le Nozze mistiche di Santa Caterina by Francesco Vanni (1601), hanging above the right-hand side altar. The last element of this cycle is Santa Caterina dona il suo mantello al povero, also by Sebastiano Folli.

The altarpieces and the smaller paintings on the back wall are complementedby an elegant series of frames, columns and frontons in polychrome marble. The other smaller paintings are similarly framed by refined painted and golden plaster frames attributed to Francesco del Monna. Also part of this complex are hand-painted tiles in fake bronze, depicting scenes from the life and Passion of Christ. A cornice with symbols from The Passion of Christ divides the inner walls in two main blocks. In the middle of the Church is the gravestone of its founder, Aurelio Chigi, attributed to Ascanio da Cortona.

The rich heritage of the Church also includes several religious furnishings, among which a wooden pulpit by Agostino Fantastici particularly stands out. There are also sculptures, reliquaries, liturgical objects and equipment, ex-votos, missals, antependia and vestments dating back to the XVII and XVIII Centuries. Some objects are even more ancient.

The old sacristy of the Church, which has recently been refurbished, contains precious silver religious ornaments, three works of art, which was previously exposed in the Pinacoteca Nazionale di Siena (National Gallery of Siena), and a painting by Sano di Pietro which had been stolen during the 1950s and was found back in an art market in 2007. The latter work of art was returned to the Fondazione in the year 2012 thanks to the local superintendence.