Unconventional superconductivity in non-centrosymmetric superconductors has attracted a considerable amount of attention. While several lanthanide-based materials have been reported previously, the number of actinide-based systems remains small. In this work, we present the discovery of a novel cubic complex non-centrosymmetric superconductor $${\text {Th}}_4{\text {Be}}_{{33}}{\text {Pt}}_{{16}}$$
Th
4
Be
33
Pt
16
($$I{\bar{4}}3d$$
I
4
¯
3
d
space group). This intermetallic cage compound displays superconductivity below $$T_{\text {c}} = 0.90 \pm 0.04$$
T
c
=
0.90
±
0.04
K, as evidenced by specific heat and resistivity data. $${\text {Th}}_4{\text {Be}}_{{33}}{\text {Pt}}_{{16}}$$
Th
4
Be
33
Pt
16
is a type-II superconductor, which has an upper critical field $${\text {H}}_{{\text {c}}2} = 0.27$$
H
c
2
=
0.27
T and a moderate Sommerfeld coefficient $$\gamma _{\text {n}} = 16.3 \pm 0.8$$
γ
n
=
16.3
±
0.8
mJ $${\text {mol}}^{-1}_{\text {Th}}$$
mol
Th
-
1
$${\text {K}}^{-2}$$
K
-
2
. A non-zero density of states at the Fermi level is evident from metallic behavior in the normal state, as well as from electronic band structure calculations. The isostructural $${\text {U}}_4{\text {Be}}_{{33}}{\text {Pt}}_{{16}}$$
U
4
Be
33
Pt
16
compound is a paramagnet with a moderately enhanced electronic mass, as indicated by the electronic specific heat coefficient $$\gamma _{\text {n}} = 200$$
γ
n
=
200
mJ $${\text {mol}}^{-1}_{\text {U}}$$
mol
U
-
1
$${\text {K}}^{-2}$$
K
-
2
and Kadowaki–Woods ratio $$A/\gamma ^2 = 1.1 \times 10^{-5}$$
A
/
γ
2
=
1.1
×
10
-
5
$$\upmu $$
μ
$$\Omega $$
Ω
cm $${\text {K}}^2$$
K
2
$${\text {mol}}_{\text {U}}^2$$
mol
U
2
(mJ)$$^{-2}$$
-
2
. Both $${\text {Th}}_4{\text {Be}}_{{33}}{\text {Pt}}_{{16}}$$
Th
4
Be
33
Pt
16
and $${\text {U}}_4{\text {Be}}_{{33}}{\text {Pt}}_{{16}}$$
U
4
Be
33
Pt
16
are crystallographically complex, each hosting 212 atoms per unit cell.