diff --git a/reactive/kotlinx-coroutines-reactive/src/main/kotlin/kotlinx/coroutines/experimental/reactive/Convert.kt b/reactive/kotlinx-coroutines-reactive/src/main/kotlin/kotlinx/coroutines/experimental/reactive/Convert.kt
index 1dbec54300..315e753a7e 100644
--- a/reactive/kotlinx-coroutines-reactive/src/main/kotlin/kotlinx/coroutines/experimental/reactive/Convert.kt
+++ b/reactive/kotlinx-coroutines-reactive/src/main/kotlin/kotlinx/coroutines/experimental/reactive/Convert.kt
@@ -16,6 +16,7 @@
 
 package kotlinx.coroutines.experimental.reactive
 
+import kotlinx.coroutines.experimental.DefaultDispatcher
 import kotlinx.coroutines.experimental.channels.ReceiveChannel
 import org.reactivestreams.Publisher
 import kotlin.coroutines.experimental.CoroutineContext
@@ -28,7 +29,7 @@ import kotlin.coroutines.experimental.CoroutineContext
  *
  * @param context -- the coroutine context from which the resulting observable is going to be signalled
  */
-public fun <T> ReceiveChannel<T>.asPublisher(context: CoroutineContext): Publisher<T> = publish(context) {
+public fun <T> ReceiveChannel<T>.asPublisher(context: CoroutineContext = DefaultDispatcher): Publisher<T> = publish(context) {
     for (t in this@asPublisher)
         send(t)
 }
diff --git a/reactive/kotlinx-coroutines-reactor/src/main/kotlin/kotlinx/coroutines/experimental/reactor/Convert.kt b/reactive/kotlinx-coroutines-reactor/src/main/kotlin/kotlinx/coroutines/experimental/reactor/Convert.kt
index c343b5c264..9eeee9ceaa 100644
--- a/reactive/kotlinx-coroutines-reactor/src/main/kotlin/kotlinx/coroutines/experimental/reactor/Convert.kt
+++ b/reactive/kotlinx-coroutines-reactor/src/main/kotlin/kotlinx/coroutines/experimental/reactor/Convert.kt
@@ -1,5 +1,6 @@
 package kotlinx.coroutines.experimental.reactor
 
+import kotlinx.coroutines.experimental.DefaultDispatcher
 import kotlinx.coroutines.experimental.Deferred
 import kotlinx.coroutines.experimental.Job
 import kotlinx.coroutines.experimental.channels.ReceiveChannel
@@ -16,7 +17,7 @@ import kotlin.coroutines.experimental.CoroutineContext
  *
  * @param context -- the coroutine context from which the resulting mono is going to be signalled
  */
-public fun Job.asMono(context: CoroutineContext): Mono<Unit> = mono(context) { this@asMono.join() }
+public fun Job.asMono(context: CoroutineContext = DefaultDispatcher): Mono<Unit> = mono(context) { this@asMono.join() }
 
 /**
  * Converts this deferred value to the hot reactive mono that signals
@@ -27,7 +28,7 @@ public fun Job.asMono(context: CoroutineContext): Mono<Unit> = mono(context) { t
  *
  * @param context -- the coroutine context from which the resulting mono is going to be signalled
  */
-public fun <T> Deferred<T?>.asMono(context: CoroutineContext): Mono<T> = mono(context) { this@asMono.await() }
+public fun <T> Deferred<T?>.asMono(context: CoroutineContext = DefaultDispatcher): Mono<T> = mono(context) { this@asMono.await() }
 
 /**
  * Converts a stream of elements received from the channel to the hot reactive flux.
@@ -37,7 +38,7 @@ public fun <T> Deferred<T?>.asMono(context: CoroutineContext): Mono<T> = mono(co
  *
  * @param context -- the coroutine context from which the resulting flux is going to be signalled
  */
-public fun <T> ReceiveChannel<T>.asFlux(context: CoroutineContext): Flux<T> = flux(context) {
+public fun <T> ReceiveChannel<T>.asFlux(context: CoroutineContext = DefaultDispatcher): Flux<T> = flux(context) {
     for (t in this@asFlux)
         send(t)
 }
\ No newline at end of file
diff --git a/reactive/kotlinx-coroutines-reactor/src/main/kotlin/kotlinx/coroutines/experimental/reactor/Flux.kt b/reactive/kotlinx-coroutines-reactor/src/main/kotlin/kotlinx/coroutines/experimental/reactor/Flux.kt
index 30d3f3db46..607567a7d8 100644
--- a/reactive/kotlinx-coroutines-reactor/src/main/kotlin/kotlinx/coroutines/experimental/reactor/Flux.kt
+++ b/reactive/kotlinx-coroutines-reactor/src/main/kotlin/kotlinx/coroutines/experimental/reactor/Flux.kt
@@ -1,5 +1,6 @@
 package kotlinx.coroutines.experimental.reactor
 
+import kotlinx.coroutines.experimental.DefaultDispatcher
 import kotlinx.coroutines.experimental.channels.ProducerScope
 import kotlinx.coroutines.experimental.reactive.publish
 import reactor.core.publisher.Flux
@@ -19,7 +20,8 @@ import kotlin.coroutines.experimental.CoroutineContext
  * | Normal completion or `close` without cause   | `onComplete`
  * | Failure with exception or `close` with cause | `onError`
  */
+@JvmOverloads // for binary compatibility with older code compiled before context had a default
 fun <T> flux(
-        context: CoroutineContext,
+        context: CoroutineContext = DefaultDispatcher,
         block: suspend ProducerScope<T>.() -> Unit
 ): Flux<T> = Flux.from(publish(context, block))