diff --git a/Project.toml b/Project.toml
index bdb339d633..7f3d26e596 100644
--- a/Project.toml
+++ b/Project.toml
@@ -31,15 +31,11 @@ Zeros = "bd1ec220-6eb4-527a-9b49-e79c3db6233b"
 
 [weakdeps]
 HDF5 = "f67ccb44-e63f-5c2f-98bd-6dc0ccc4ba2f"
-Observers = "338f10d5-c7f1-4033-a7d1-f9dec39bcaa0"
-PackageCompiler = "9b87118b-4619-50d2-8e1e-99f35a4d4d9d"
 VectorInterface = "409d34a3-91d5-4945-b6ec-7529ddf182d8"
 ZygoteRules = "700de1a5-db45-46bc-99cf-38207098b444"
 
 [extensions]
 ITensorsHDF5Ext = "HDF5"
-ITensorsObserversExt = "Observers"
-ITensorsPackageCompilerExt = "PackageCompiler"
 ITensorsVectorInterfaceExt = "VectorInterface"
 ITensorsZygoteRulesExt = "ZygoteRules"
 
@@ -57,8 +53,6 @@ KrylovKit = "0.4.2, 0.5, 0.6, 0.7, 0.8"
 LinearAlgebra = "1.6"
 LinearMaps = "3"
 NDTensors = "0.3.34"
-Observers = "0.2"
-PackageCompiler = "1, 2"
 PackageExtensionCompat = "1"
 Pkg = "1.6"
 Printf = "1.6"
@@ -78,7 +72,5 @@ julia = "1.10"
 [extras]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
 HDF5 = "f67ccb44-e63f-5c2f-98bd-6dc0ccc4ba2f"
-Observers = "338f10d5-c7f1-4033-a7d1-f9dec39bcaa0"
-PackageCompiler = "9b87118b-4619-50d2-8e1e-99f35a4d4d9d"
 VectorInterface = "409d34a3-91d5-4945-b6ec-7529ddf182d8"
 ZygoteRules = "700de1a5-db45-46bc-99cf-38207098b444"
diff --git a/ext/ITensorsObserversExt/ITensorsObserversExt.jl b/ext/ITensorsObserversExt/ITensorsObserversExt.jl
deleted file mode 100644
index f5829b99be..0000000000
--- a/ext/ITensorsObserversExt/ITensorsObserversExt.jl
+++ /dev/null
@@ -1,11 +0,0 @@
-module ITensorsObserversExt
-
-using Observers: Observers
-using Observers.DataFrames: AbstractDataFrame
-using ITensors.ITensorMPS: ITensorMPS
-
-function ITensorMPS.update_observer!(observer::AbstractDataFrame; kwargs...)
-  return Observers.update!(observer; kwargs...)
-end
-
-end
diff --git a/ext/ITensorsPackageCompilerExt/ITensorsPackageCompilerExt.jl b/ext/ITensorsPackageCompilerExt/ITensorsPackageCompilerExt.jl
deleted file mode 100644
index 3bb7b57ac1..0000000000
--- a/ext/ITensorsPackageCompilerExt/ITensorsPackageCompilerExt.jl
+++ /dev/null
@@ -1,3 +0,0 @@
-module ITensorsPackageCompilerExt
-include("compile.jl")
-end
diff --git a/ext/ITensorsPackageCompilerExt/compile.jl b/ext/ITensorsPackageCompilerExt/compile.jl
deleted file mode 100644
index 5d08011abd..0000000000
--- a/ext/ITensorsPackageCompilerExt/compile.jl
+++ /dev/null
@@ -1,26 +0,0 @@
-using NDTensors: @Algorithm_str
-using ITensors: ITensors
-using PackageCompiler: PackageCompiler
-
-function ITensors.compile(
-  ::Algorithm"PackageCompiler";
-  dir::AbstractString=ITensors.default_compile_dir(),
-  filename::AbstractString=ITensors.default_compile_filename(),
-)
-  if !isdir(dir)
-    println("""The directory "$dir" doesn't exist yet, creating it now.""")
-    println()
-    mkdir(dir)
-  end
-  path = joinpath(dir, filename)
-  println(
-    """Creating the system image "$path" containing the compiled version of ITensors. This may take a few minutes.""",
-  )
-  PackageCompiler.create_sysimage(
-    :ITensors;
-    sysimage_path=path,
-    precompile_execution_file=joinpath(@__DIR__, "precompile_itensors.jl"),
-  )
-  println(ITensors.compile_note(; dir, filename))
-  return path
-end
diff --git a/ext/ITensorsPackageCompilerExt/precompile_itensors.jl b/ext/ITensorsPackageCompilerExt/precompile_itensors.jl
deleted file mode 100644
index 4d5d639359..0000000000
--- a/ext/ITensorsPackageCompilerExt/precompile_itensors.jl
+++ /dev/null
@@ -1,28 +0,0 @@
-using ITensors.ITensorMPS: MPO, OpSum, dmrg, random_mps, siteinds
-
-# TODO: This uses all of the tests to make
-# precompile statements, but takes a long time
-# (e.g. 700 seconds).
-# Try again with later versions of PackageCompiler
-#
-# include(joinpath(joinpath(dirname(dirname(@__DIR__)),
-#                           test"),
-#                  "runtests.jl"))
-
-function main(; N, dmrg_kwargs)
-  opsum = OpSum()
-  for j in 1:(N - 1)
-    opsum += 0.5, "S+", j, "S-", j + 1
-    opsum += 0.5, "S-", j, "S+", j + 1
-    opsum += "Sz", j, "Sz", j + 1
-  end
-  for conserve_qns in (false, true)
-    sites = siteinds("S=1", N; conserve_qns)
-    H = MPO(opsum, sites)
-    ψ0 = random_mps(sites, j -> isodd(j) ? "↑" : "↓"; linkdims=2)
-    dmrg(H, ψ0; outputlevel=0, dmrg_kwargs...)
-  end
-  return nothing
-end
-
-main(; N=6, dmrg_kwargs=(; nsweeps=3, maxdim=10, cutoff=1e-13))